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Berné O, Habart E, Peeters E, Schroetter I, Canin A, Sidhu A, Chown R, Bron E, Haworth TJ, Klaassen P, Trahin B, Van De Putte D, Alarcón F, Zannese M, Abergel A, Bergin EA, Bernard-Salas J, Boersma C, Cami J, Cuadrado S, Dartois E, Dicken D, Elyajouri M, Fuente A, Goicoechea JR, Gordon KD, Issa L, Joblin C, Kannavou O, Khan B, Lacinbala O, Languignon D, Le Gal R, Maragkoudakis A, Meshaka R, Okada Y, Onaka T, Pasquini S, Pound MW, Robberto M, Röllig M, Schefter B, Schirmer T, Simmer T, Tabone B, Tielens AGGM, Vicente S, Wolfire MG, Aleman I, Allamandola L, Auchettl R, Baratta GA, Baruteau C, Bejaoui S, Bera PP, Black JH, Boulanger F, Bouwman J, Brandl B, Brechignac P, Brünken S, Buragohain M, Burkhardt A, Candian A, Cazaux S, Cernicharo J, Chabot M, Chakraborty S, Champion J, Colgan SWJ, Cooke IR, Coutens A, Cox NLJ, Demyk K, Meyer JD, Engrand C, Foschino S, García-Lario P, Gavilan L, Gerin M, Godard M, Gottlieb CA, Guillard P, Gusdorf A, Hartigan P, He J, Herbst E, Hornekaer L, Jäger C, Janot-Pacheco E, Kaufman M, Kemper F, Kendrew S, Kirsanova MS, Knight C, Kwok S, Labiano Á, Lai TSY, Lee TJ, Lefloch B, Le Petit F, Li A, Linz H, Mackie CJ, Madden SC, Mascetti J, McGuire BA, Merino P, Micelotta ER, Morse JA, Mulas G, Neelamkodan N, Ohsawa R, Paladini R, Palumbo ME, Pathak A, Pendleton YJ, Petrignani A, Pino T, Puga E, Rangwala N, Rapacioli M, Ricca A, Roman-Duval J, Roueff E, Rouillé G, Salama F, Sales DA, Sandstrom K, Sarre P, Sciamma-O'Brien E, Sellgren K, Shannon MJ, Simonnin A, Shenoy SS, Teyssier D, Thomas RD, Togi A, Verstraete L, Witt AN, Wootten A, Ysard N, Zettergren H, Zhang Y, Zhang ZE, Zhen J. A far-ultraviolet-driven photoevaporation flow observed in a protoplanetary disk. Science 2024; 383:988-992. [PMID: 38422128 DOI: 10.1126/science.adh2861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 01/12/2024] [Indexed: 03/02/2024]
Abstract
Most low-mass stars form in stellar clusters that also contain massive stars, which are sources of far-ultraviolet (FUV) radiation. Theoretical models predict that this FUV radiation produces photodissociation regions (PDRs) on the surfaces of protoplanetary disks around low-mass stars, which affects planet formation within the disks. We report James Webb Space Telescope and Atacama Large Millimeter Array observations of a FUV-irradiated protoplanetary disk in the Orion Nebula. Emission lines are detected from the PDR; modeling their kinematics and excitation allowed us to constrain the physical conditions within the gas. We quantified the mass-loss rate induced by the FUV irradiation and found that it is sufficient to remove gas from the disk in less than a million years. This is rapid enough to affect giant planet formation in the disk.
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Affiliation(s)
- Olivier Berné
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, Centre National de la Recherche Scientifique (CNRS), Centre National d'Etudes Spatiales, 31028 Toulouse, France
| | - Emilie Habart
- Institut d'Astrophysique Spatiale, Université Paris-Saclay, CNRS, 91405 Orsay, France
| | - Els Peeters
- Department of Physics and Astronomy, The University of Western Ontario, London, ON N6A 3K7, Canada
- Institute for Earth and Space Exploration, The University of Western Ontario, London, ON N6A 3K7, Canada
- Carl Sagan Center, Search for ExtraTerrestrial Intelligence Institute, Mountain View, CA 94043, USA
| | - Ilane Schroetter
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, Centre National de la Recherche Scientifique (CNRS), Centre National d'Etudes Spatiales, 31028 Toulouse, France
| | - Amélie Canin
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, Centre National de la Recherche Scientifique (CNRS), Centre National d'Etudes Spatiales, 31028 Toulouse, France
| | - Ameek Sidhu
- Department of Physics and Astronomy, The University of Western Ontario, London, ON N6A 3K7, Canada
- Institute for Earth and Space Exploration, The University of Western Ontario, London, ON N6A 3K7, Canada
| | - Ryan Chown
- Department of Physics and Astronomy, The University of Western Ontario, London, ON N6A 3K7, Canada
- Institute for Earth and Space Exploration, The University of Western Ontario, London, ON N6A 3K7, Canada
| | - Emeric Bron
- Laboratoire d'Etudes du Rayonnement et de la Matière, Observatoire de Paris, Université Paris Science et Lettres, CNRS, Sorbonne Universités, F-92190 Meudon, France
| | - Thomas J Haworth
- School of Physics and Astronomy, Queen Mary University of London, London E1 4NS, UK
| | - Pamela Klaassen
- UK Astronomy Technology Centre, Royal Observatory Edinburgh, Blackford Hill EH9 3HJ, UK
| | - Boris Trahin
- Institut d'Astrophysique Spatiale, Université Paris-Saclay, CNRS, 91405 Orsay, France
| | | | - Felipe Alarcón
- Department of Astronomy, University of Michigan, Ann Arbor, MI 48109, USA
| | - Marion Zannese
- Institut d'Astrophysique Spatiale, Université Paris-Saclay, CNRS, 91405 Orsay, France
| | - Alain Abergel
- Institut d'Astrophysique Spatiale, Université Paris-Saclay, CNRS, 91405 Orsay, France
| | - Edwin A Bergin
- Department of Astronomy, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jeronimo Bernard-Salas
- ACRI-ST, Centre d'Etudes et de Recherche de Grasse, F-06130 Grasse, France
- Innovative Common Laboratory for Space Spectroscopy, 06130 Grasse, France
| | | | - Jan Cami
- Department of Physics and Astronomy, The University of Western Ontario, London, ON N6A 3K7, Canada
- Institute for Earth and Space Exploration, The University of Western Ontario, London, ON N6A 3K7, Canada
- Carl Sagan Center, Search for ExtraTerrestrial Intelligence Institute, Mountain View, CA 94043, USA
| | - Sara Cuadrado
- Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas, 28006 Madrid, Spain
| | - Emmanuel Dartois
- Institut des Sciences Moléculaires d'Orsay, Université Paris-Saclay, CNRS, 91405 Orsay, France
| | - Daniel Dicken
- Institut d'Astrophysique Spatiale, Université Paris-Saclay, CNRS, 91405 Orsay, France
| | - Meriem Elyajouri
- Institut d'Astrophysique Spatiale, Université Paris-Saclay, CNRS, 91405 Orsay, France
| | - Asunción Fuente
- Centro de Astrobiología, Consejo Superior de Investigaciones Científicas, and Instituto Nacional de Técnica Aeroespacial, 28850 Torrejón de Ardoz, Spain
| | - Javier R Goicoechea
- Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas, 28006 Madrid, Spain
| | - Karl D Gordon
- Space Telescope Science Institute, Baltimore, MD 21218, USA
- Johns Hopkins University, Baltimore, MD 21218, USA
| | - Lina Issa
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, Centre National de la Recherche Scientifique (CNRS), Centre National d'Etudes Spatiales, 31028 Toulouse, France
| | - Christine Joblin
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, Centre National de la Recherche Scientifique (CNRS), Centre National d'Etudes Spatiales, 31028 Toulouse, France
| | - Olga Kannavou
- Institut d'Astrophysique Spatiale, Université Paris-Saclay, CNRS, 91405 Orsay, France
| | - Baria Khan
- Department of Physics and Astronomy, The University of Western Ontario, London, ON N6A 3K7, Canada
| | - Ozan Lacinbala
- Institut d'Astrophysique Spatiale, Université Paris-Saclay, CNRS, 91405 Orsay, France
| | - David Languignon
- Laboratoire d'Etudes du Rayonnement et de la Matière, Observatoire de Paris, Université Paris Science et Lettres, CNRS, Sorbonne Universités, F-92190 Meudon, France
| | - Romane Le Gal
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, Centre National de la Recherche Scientifique (CNRS), Centre National d'Etudes Spatiales, 31028 Toulouse, France
- Institut de Planétologie et d'Astrophysique de Grenoble, Université Grenoble Alpes, CNRS, F-38000 Grenoble, France
- Institut de Radioastronomie Millimétrique, F-38406 Saint-Martin d'Hères, France
| | | | - Raphael Meshaka
- Institut d'Astrophysique Spatiale, Université Paris-Saclay, CNRS, 91405 Orsay, France
| | - Yoko Okada
- I. Physikalisches Institut, Universität zu Köln, 50937 Köln, Germany
| | - Takashi Onaka
- Department of Astronomy, Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan
- Department of Physics, Faculty of Science and Engineering, Meisei University, Hino, Tokyo 191-8506, Japan
| | - Sofia Pasquini
- Department of Physics and Astronomy, The University of Western Ontario, London, ON N6A 3K7, Canada
| | - Marc W Pound
- Astronomy Department, University of Maryland, College Park, MD 20742, USA
| | - Massimo Robberto
- Space Telescope Science Institute, Baltimore, MD 21218, USA
- Johns Hopkins University, Baltimore, MD 21218, USA
| | - Markus Röllig
- I. Physikalisches Institut, Universität zu Köln, 50937 Köln, Germany
| | - Bethany Schefter
- Department of Physics and Astronomy, The University of Western Ontario, London, ON N6A 3K7, Canada
| | - Thiébaut Schirmer
- Institut d'Astrophysique Spatiale, Université Paris-Saclay, CNRS, 91405 Orsay, France
- Department of Space, Earth and Environment, Chalmers University of Technology, Onsala Space Observatory, SE-439 92 Onsala, Sweden
| | - Thomas Simmer
- Institut d'Astrophysique Spatiale, Université Paris-Saclay, CNRS, 91405 Orsay, France
| | - Benoit Tabone
- Institut d'Astrophysique Spatiale, Université Paris-Saclay, CNRS, 91405 Orsay, France
| | - Alexander G G M Tielens
- Astronomy Department, University of Maryland, College Park, MD 20742, USA
- Leiden Observatory, Leiden University, 2300 RA Leiden, Netherlands
| | - Sílvia Vicente
- Instituto de Astrofísica e Ciências do Espaço, P-1349-018 Lisboa, Portugal
| | - Mark G Wolfire
- Astronomy Department, University of Maryland, College Park, MD 20742, USA
| | - Isabel Aleman
- Instituto de Física e Química, Universidade Federal de Itajubá, Itajubá, Brazil
| | - Louis Allamandola
- Astronomy Department, University of Maryland, College Park, MD 20742, USA
- Bay Area Environmental Research Institute, Moffett Field, CA 94035, USA
| | - Rebecca Auchettl
- Australian Synchrotron, Australian Nuclear Science and Technology Organisation, Victoria, Australia
| | | | - Clément Baruteau
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, Centre National de la Recherche Scientifique (CNRS), Centre National d'Etudes Spatiales, 31028 Toulouse, France
| | - Salma Bejaoui
- Astronomy Department, University of Maryland, College Park, MD 20742, USA
| | - Partha P Bera
- Astronomy Department, University of Maryland, College Park, MD 20742, USA
- Bay Area Environmental Research Institute, Moffett Field, CA 94035, USA
| | - John H Black
- Department of Space, Earth, and Environment, Chalmers University of Technology, Onsala Space Observatory, 43992 Onsala, Sweden
| | - Francois Boulanger
- Laboratoire de Physique de l'École Normale Supérieure, Université Paris Science et Lettres, CNRS, Sorbonne Université, Université de Paris, 75005, Paris, France
| | - Jordy Bouwman
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303, USA
- Department of Chemistry, University of Colorado, Boulder, CO 80309, USA
- Institute for Modeling Plasma, Atmospheres, and Cosmic Dust, University of Colorado, Boulder, CO 80303, USA
| | - Bernhard Brandl
- I. Physikalisches Institut, Universität zu Köln, 50937 Köln, Germany
- Faculty of Aerospace Engineering, Delft University of Technology, 2629 HS Delft, Netherlands
| | | | - Sandra Brünken
- Institute for Molecules and Materials, Free-Electron Lasers for Infrared eXperiments Laboratory, Radboud University, 6525 ED Nijmegen, Netherlands
| | | | - Andrew Burkhardt
- Department of Physics, Wellesley College, Wellesley, MA 02481, USA
| | - Alessandra Candian
- I. Physikalisches Institut, Universität zu Köln, 50937 Köln, Germany
- Anton Pannekoek Institute for Astronomy, University of Amsterdam, 1098 XH Amsterdam, Netherlands
| | - Stéphanie Cazaux
- Department of Astronomy, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jose Cernicharo
- Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas, 28006 Madrid, Spain
| | - Marin Chabot
- Laboratoire de Physique des deux infinis Irène Joliot-Curie, Université Paris-Saclay, CNRS, 91405 Orsay Cedex, France
| | - Shubhadip Chakraborty
- Institut de Physique de Rennes, CNRS, Université de Rennes 1, 35042 Rennes, France
- Department of Chemistry, Gandhi Institute of Technology and Management, Bangalore, India
| | - Jason Champion
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, Centre National de la Recherche Scientifique (CNRS), Centre National d'Etudes Spatiales, 31028 Toulouse, France
| | - Sean W J Colgan
- Department of Space, Earth and Environment, Chalmers University of Technology, Onsala Space Observatory, SE-439 92 Onsala, Sweden
| | - Ilsa R Cooke
- Department of Chemistry, The University of British Columbia, Vancouver, BC, Canada
| | - Audrey Coutens
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, Centre National de la Recherche Scientifique (CNRS), Centre National d'Etudes Spatiales, 31028 Toulouse, France
| | - Nick L J Cox
- ACRI-ST, Centre d'Etudes et de Recherche de Grasse, F-06130 Grasse, France
- Innovative Common Laboratory for Space Spectroscopy, 06130 Grasse, France
| | - Karine Demyk
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, Centre National de la Recherche Scientifique (CNRS), Centre National d'Etudes Spatiales, 31028 Toulouse, France
| | | | - Cécile Engrand
- Laboratoire de Physique des deux infinis Irène Joliot-Curie, Université Paris-Saclay, CNRS, 91405 Orsay Cedex, France
| | - Sacha Foschino
- Institute for Earth and Space Exploration, The University of Western Ontario, London, ON N6A 3K7, Canada
| | | | - Lisseth Gavilan
- Department of Space, Earth and Environment, Chalmers University of Technology, Onsala Space Observatory, SE-439 92 Onsala, Sweden
| | - Maryvonne Gerin
- Laboratoire d'Etudes du Rayonnement et de la Matière, Observatoire de Paris, Paris Science et Lettres University, Sorbonne Université, 75014, Paris, France
| | - Marie Godard
- ACRI-ST, Centre d'Etudes et de Recherche de Grasse, F-06130 Grasse, France
| | - Carl A Gottlieb
- Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, USA
| | - Pierre Guillard
- Institut d'Astrophysique de Paris, Sorbonne Université, CNRS, 75014 Paris, France
- Institut Universitaire de France, Ministère de l'Enseignement Supérieur et de la Recherche, 75231 Paris, France
| | - Antoine Gusdorf
- Laboratoire de Physique de l'École Normale Supérieure, Université Paris Science et Lettres, CNRS, Sorbonne Université, Université de Paris, 75005, Paris, France
- Laboratoire d'Etudes du Rayonnement et de la Matière, Observatoire de Paris, Paris Science et Lettres University, Sorbonne Université, 75014, Paris, France
| | - Patrick Hartigan
- Department of Physics and Astronomy, Rice University, Houston, TX 77005, USA
| | - Jinhua He
- Yunnan Observatories, Chinese Academy of Sciences, Kunming 650216, China
- Chinese Academy of Sciences South America Center for Astronomy, National Astronomical Observatories, Beijing 100101, China
- Departamento de Astronomía, Universidad de Chile, Santiago, Chile
| | - Eric Herbst
- Departments of Chemistry and Astronomy, University of Virginia, Charlottesville, VA 22904, USA
| | - Liv Hornekaer
- Center for Interstellar Catalysis, Department of Physics and Astronomy, Aarhus University, 8000 Aarhus C, Denmark
| | - Cornelia Jäger
- Institute of Solid State Physics, Max Planck Institute for Astronomy, Friedrich Schiller University Jena, 07743 Jena, Germany
| | - Eduardo Janot-Pacheco
- Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo, 05509-090 São Paulo, Brazil
| | - Michael Kaufman
- Department of Physics and Astronomy, San José State University, San Jose, CA 95192, USA
| | - Francisca Kemper
- Institut de Ciencies de l'Espai, Centro Superior de Investigacion Cientifica, E-08193, Barcelona, Spain
- Institución Catalana de Investigación y Estudios Avanzados, E-08010 Barcelona, Spain
- Institut d'Estudis Espacials de Catalunya, E-08034 Barcelona, Spain
| | - Sarah Kendrew
- European Space Agency, Space Telescope Science Institute, Baltimore, MD 21218, USA
| | - Maria S Kirsanova
- Institute of Astronomy, Russian Academy of Sciences, 119017 Moscow, Russia
| | - Collin Knight
- Department of Physics and Astronomy, The University of Western Ontario, London, ON N6A 3K7, Canada
| | - Sun Kwok
- Department of Earth, Ocean, and Atmospheric Sciences, University of British Columbia, BC V6T 1Z4, Canada
| | - Álvaro Labiano
- Telespazio UK, European Space Agency, E-28692 Villanueva de la Cañada, Madrid, Spain
| | - Thomas S-Y Lai
- Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125, USA
| | - Timothy J Lee
- Department of Space, Earth and Environment, Chalmers University of Technology, Onsala Space Observatory, SE-439 92 Onsala, Sweden
| | - Bertrand Lefloch
- Leiden Observatory, Leiden University, 2300 RA Leiden, Netherlands
| | | | - Aigen Li
- Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211, USA
| | - Hendrik Linz
- Max Planck Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany
| | - Cameron J Mackie
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Pitzer Center for Theoretical Chemistry, College of Chemistry, University of California, Berkeley, CA, USA
| | - Suzanne C Madden
- Astrophysics, Instrumentation and Modelling, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, CNRS, Université Paris-Saclay, Université Paris Diderot, Sorbonne Paris Cité, 91191 Gif-sur-Yvette, France
| | - Joëlle Mascetti
- Institut des Sciences Moléculaires, CNRS, Université de Bordeaux, 33405 Talence, France
| | - Brett A McGuire
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- National Radio Astronomy Observatory, Charlottesville, VA 22903, USA
| | - Pablo Merino
- Instituto de Ciencia de Materiales de Madrid, Centro Superior de Investigacion Cientifica, E28049, Madrid, Spain
| | | | - Jon A Morse
- Steward Observatory, University of Arizona, Tucson, AZ 85721, USA
| | - Giacomo Mulas
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, Centre National de la Recherche Scientifique (CNRS), Centre National d'Etudes Spatiales, 31028 Toulouse, France
- Osservatorio Astronomico di Cagliari, Instituto Nazionale di Astrofisca, 09047 Selargius, Italy
| | - Naslim Neelamkodan
- Department of Physics, College of Science, United Arab Emirates University, Al-Ain 15551, United Arab Emirates
| | - Ryou Ohsawa
- National Astronomical Observatory of Japan, Tokyo 181-8588, Japan
| | - Roberta Paladini
- Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125, USA
| | | | - Amit Pathak
- Department of Physics, Institute of Science, Banaras Hindu University, Varanasi 221005, India
| | - Yvonne J Pendleton
- Department of Physics, University of Central Florida, Orlando, FL 32816, USA
| | - Annemieke Petrignani
- Van't Hoff Institute for Molecular Sciences, University of Amsterdam, 1090 GD Amsterdam, Netherlands
| | - Thomas Pino
- Innovative Common Laboratory for Space Spectroscopy, 06130 Grasse, France
| | - Elena Puga
- European Space Agency, Villanueva de la Cañada, E-28692 Madrid, Spain
| | | | - Mathias Rapacioli
- Laboratoire de Chimie et Physique Quantiques, Université de Toulouse, CNRS, Toulouse, France
| | - Alessandra Ricca
- Department of Physics and Astronomy, The University of Western Ontario, London, ON N6A 3K7, Canada
- Department of Space, Earth and Environment, Chalmers University of Technology, Onsala Space Observatory, SE-439 92 Onsala, Sweden
| | - Julia Roman-Duval
- Institut des Sciences Moléculaires d'Orsay, Université Paris-Saclay, CNRS, 91405 Orsay, France
| | - Evelyne Roueff
- Department of Astronomy, University of Michigan, Ann Arbor, MI 48109, USA
| | - Gaël Rouillé
- Institute of Solid State Physics, Max Planck Institute for Astronomy, Friedrich Schiller University Jena, 07743 Jena, Germany
| | - Farid Salama
- NASA Ames Research Center, Moffett Field, CA 94035, USA
| | - Dinalva A Sales
- Instituto de Matemática, Estatística e Física, Universidade Federal do Rio Grande, 96201-900, Rio Grande, Brazil
| | - Karin Sandstrom
- Center for Astrophysics and Space Sciences, Department of Physics, University of California, San Diego, CA 92093, USA
| | - Peter Sarre
- School of Chemistry, The University of Nottingham, Nottingham NG7 2RD, UK
| | | | - Kris Sellgren
- Astronomy Department, Ohio State University, Columbus, OH 43210, USA
| | | | - Adrien Simonnin
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, Centre National de la Recherche Scientifique (CNRS), Centre National d'Etudes Spatiales, 31028 Toulouse, France
| | | | - David Teyssier
- European Space Agency, Villanueva de la Cañada, E-28692 Madrid, Spain
| | - Richard D Thomas
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
| | - Aditya Togi
- Department of Physics, Texas State University, San Marcos, TX 78666, USA
| | - Laurent Verstraete
- Institut d'Astrophysique Spatiale, Université Paris-Saclay, CNRS, 91405 Orsay, France
| | - Adolf N Witt
- Ritter Astrophysical Research Center, University of Toledo, Toledo, OH 43606, USA
| | - Alwyn Wootten
- National Radio Astronomy Observatory, Charlottesville, VA 22903, USA
| | - Nathalie Ysard
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, Centre National de la Recherche Scientifique (CNRS), Centre National d'Etudes Spatiales, 31028 Toulouse, France
- Institut d'Astrophysique Spatiale, Université Paris-Saclay, CNRS, 91405 Orsay, France
| | | | - Yong Zhang
- School of Physics and Astronomy, Sun Yat-sen University, Zhuhai 519000, China
| | - Ziwei E Zhang
- Star and Planet Formation Laboratory, Rikagaku Kenkyusho Cluster for Pioneering Research, Saitama 351-0198, Japan
| | - Junfeng Zhen
- Key Laboratory of Crust-Mantle Materials and Environment, Chinese Academy of Science, University of Science and Technology of China, Anhui 230026, China
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M Nair A, Leboucher H, Toucouere L, Zamith S, Joblin C, L'Hermite JM, Marciniak A, Simon A. Diversity of protonated mixed pyrene-water clusters investigated by collision induced dissociation. Phys Chem Chem Phys 2024; 26:5947-5961. [PMID: 38294026 PMCID: PMC10866126 DOI: 10.1039/d3cp05734h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Accepted: 01/11/2024] [Indexed: 02/01/2024]
Abstract
Protonated mixed pyrene-water clusters, (Py)m(H2O)nH+, where m = [1-3] and n = [1-10], are generated using a cryogenic molecular cluster source. Subsequently, the mass-selected mixed clusters undergo controlled collisions with rare gases, and the resulting fragmentation mass spectra are meticulously analyzed to discern distinct fragmentation channels. Notably, protonated water cluster fragments emerge for n ≥ 3, whereas they are absent for n = 1 and 2. The experimental results are complemented by theoretical calculations of structures and energetics for (Py)(H2O)nH+ with n = [1-4]. These calculations reveal a shift in proton localization, transitioning from the pyrene molecule for n = 1 and 2 to water molecules for n ≥ 3. The results support a formation scenario wherein water molecules attach to protonated pyrene PyH+ seeds, and, by extension, to (Py)2H+ and (Py)3H+ seeds. Various isomers are identified, corresponding to potential protonation sites on the pyrene molecule. Protonated polycyclic aromatic hydrocarbons are likely to be formed in cold, dense interstellar clouds and protoplanetary disks due to the high proton affinity of these species. Our findings show that the presence of protonated PAHs in these environments could lead to the formation of water clusters and mixed carbon-water nanograins, having a potential impact on the water cycle in regions of planet formation.
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Affiliation(s)
- Arya M Nair
- Laboratoire Collisions Agrégats Réactivité (LCAR/FERMI), UMR5589, Université Toulouse III - Paul Sabatier and CNRS, 118 Route de Narbonne, F-31062 Toulouse, France.
- Institut de Recherche en Astrophysique et Planétologie (IRAP), Université Toulouse III - Paul Sabatier, CNRS, CNES, 9 Avenue du Colonel Roche, F-31028 Toulouse, France
| | - Héloïse Leboucher
- Laboratoire de Chimie et Physique Quantiques LCPQ/FERMI, Université Toulouse III - Paul Sabatier and CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
| | - Lorris Toucouere
- Laboratoire de Chimie et Physique Quantiques LCPQ/FERMI, Université Toulouse III - Paul Sabatier and CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
| | - Sébastien Zamith
- Laboratoire Collisions Agrégats Réactivité (LCAR/FERMI), UMR5589, Université Toulouse III - Paul Sabatier and CNRS, 118 Route de Narbonne, F-31062 Toulouse, France.
| | - Christine Joblin
- Institut de Recherche en Astrophysique et Planétologie (IRAP), Université Toulouse III - Paul Sabatier, CNRS, CNES, 9 Avenue du Colonel Roche, F-31028 Toulouse, France
| | - Jean-Marc L'Hermite
- Laboratoire Collisions Agrégats Réactivité (LCAR/FERMI), UMR5589, Université Toulouse III - Paul Sabatier and CNRS, 118 Route de Narbonne, F-31062 Toulouse, France.
| | - Alexandre Marciniak
- Laboratoire Collisions Agrégats Réactivité (LCAR/FERMI), UMR5589, Université Toulouse III - Paul Sabatier and CNRS, 118 Route de Narbonne, F-31062 Toulouse, France.
| | - Aude Simon
- Laboratoire de Chimie et Physique Quantiques LCPQ/FERMI, Université Toulouse III - Paul Sabatier and CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
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Zamith S, Kassem A, L'Hermite JM, Joblin C, Cuny J. Threshold collision induced dissociation of protonated water clusters. J Chem Phys 2023; 159:184302. [PMID: 37955320 DOI: 10.1063/5.0167551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 10/19/2023] [Indexed: 11/14/2023] Open
Abstract
We report threshold collision induced dissociation experiments on protonated water clusters thermalized at low temperature for sizes n = 19-23. Fragmentation cross sections are recorded as a function of the collision energy and analyzed with a statistical model. This model allows us to account for dissociation cascades and provides values for the dissociation energies of each cluster. These values, averaging around 0.47 eV, are in good agreement with theoretical predictions at various levels of theory. Furthermore, the dissociation energies show a trend for the n = 21 magic and n = 22 anti-magic numbers relative to their neighbours, which is also in agreement with theory. These results provide further evidence to resolve the disagreement between previously published experimental values. A careful quantitative treatment of cascade dissociation in this model introduces interdependence between the dissociation energies of neighboring sizes, which reduces the number of free fitting parameters and improves both reliability and uncertainties on absolute dissociation energies deduced from experiments.
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Affiliation(s)
- Sébastien Zamith
- Laboratoire Collisions Agrégats Réactivité (LCAR/FERMI), UMR5589, Université Toulouse III - Paul Sabatier, CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
| | - Ali Kassem
- Laboratoire Collisions Agrégats Réactivité (LCAR/FERMI), UMR5589, Université Toulouse III - Paul Sabatier, CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
| | - Jean-Marc L'Hermite
- Laboratoire Collisions Agrégats Réactivité (LCAR/FERMI), UMR5589, Université Toulouse III - Paul Sabatier, CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
| | - Christine Joblin
- Institut de Recherche en Astrophysique et Planétologie (IRAP), UMR5277, Université Toulouse III - Paul Sabatier, CNRS, CNES, 9 avenue du Colonel Roche, F-31028 Toulouse, France
| | - Jérôme Cuny
- Laboratoire de Chimie et Physique Quantiques LCPQ/FERMI, Université Toulouse III - Paul Sabatier, CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
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4
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Berné O, Martin-Drumel MA, Schroetter I, Goicoechea JR, Jacovella U, Gans B, Dartois E, Coudert LH, Bergin E, Alarcon F, Cami J, Roueff E, Black JH, Asvany O, Habart E, Peeters E, Canin A, Trahin B, Joblin C, Schlemmer S, Thorwirth S, Cernicharo J, Gerin M, Tielens A, Zannese M, Abergel A, Bernard-Salas J, Boersma C, Bron E, Chown R, Cuadrado S, Dicken D, Elyajouri M, Fuente A, Gordon KD, Issa L, Kannavou O, Khan B, Lacinbala O, Languignon D, Le Gal R, Maragkoudakis A, Meshaka R, Okada Y, Onaka T, Pasquini S, Pound MW, Robberto M, Röllig M, Schefter B, Schirmer T, Sidhu A, Tabone B, Van De Putte D, Vicente S, Wolfire MG. Formation of the methyl cation by photochemistry in a protoplanetary disk. Nature 2023; 621:56-59. [PMID: 37364766 DOI: 10.1038/s41586-023-06307-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 06/09/2023] [Indexed: 06/28/2023]
Abstract
Forty years ago, it was proposed that gas-phase organic chemistry in the interstellar medium can be initiated by the methyl cation CH3+ (refs. 1-3), but so far it has not been observed outside the Solar System4,5. Alternative routes involving processes on grain surfaces have been invoked6,7. Here we report James Webb Space Telescope observations of CH3+ in a protoplanetary disk in the Orion star-forming region. We find that gas-phase organic chemistry is activated by ultraviolet irradiation.
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Affiliation(s)
- Olivier Berné
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, CNRS, CNES, UPS, Toulouse, France.
| | | | - Ilane Schroetter
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, CNRS, CNES, UPS, Toulouse, France
| | | | - Ugo Jacovella
- Institut des Sciences Moléculaires d'Orsay, Université Paris-Saclay, CNRS, Orsay, France
| | - Bérenger Gans
- Institut des Sciences Moléculaires d'Orsay, Université Paris-Saclay, CNRS, Orsay, France
| | - Emmanuel Dartois
- Institut des Sciences Moléculaires d'Orsay, Université Paris-Saclay, CNRS, Orsay, France
| | - Laurent H Coudert
- Institut des Sciences Moléculaires d'Orsay, Université Paris-Saclay, CNRS, Orsay, France
| | - Edwin Bergin
- Department of Astronomy, University of Michigan, Ann Arbor, MI, USA
| | - Felipe Alarcon
- Department of Astronomy, University of Michigan, Ann Arbor, MI, USA
| | - Jan Cami
- Department of Physics and Astronomy, The University of Western Ontario, London, Ontario, Canada
- Institute for Earth and Space Exploration, The University of Western Ontario, London, Ontario, Canada
- Carl Sagan Center, SETI Institute, Mountain View, CA, USA
| | - Evelyne Roueff
- LERMA, Observatoire de Paris, PSL University, Sorbonne Université, CNRS, Meudon, France
| | - John H Black
- Department of Space, Earth, and Environment, Chalmers University of Technology, Onsala Space Observatory, Onsala, Sweden
| | - Oskar Asvany
- I. Physikalisches Institut, Universität zu Köln, Cologne, Germany
| | - Emilie Habart
- Institut d'Astrophysique Spatiale, Université Paris-Saclay CNRS, Orsay, France
| | - Els Peeters
- Department of Physics and Astronomy, The University of Western Ontario, London, Ontario, Canada
- Institute for Earth and Space Exploration, The University of Western Ontario, London, Ontario, Canada
- Carl Sagan Center, SETI Institute, Mountain View, CA, USA
| | - Amelie Canin
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, CNRS, CNES, UPS, Toulouse, France
| | - Boris Trahin
- Institut d'Astrophysique Spatiale, Université Paris-Saclay CNRS, Orsay, France
| | - Christine Joblin
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, CNRS, CNES, UPS, Toulouse, France
| | | | - Sven Thorwirth
- I. Physikalisches Institut, Universität zu Köln, Cologne, Germany
| | | | - Maryvonne Gerin
- LERMA, Observatoire de Paris, PSL University, Sorbonne Université, CNRS, Meudon, France
| | - Alexander Tielens
- Leiden Observatory, Leiden University, Leiden, the Netherlands
- Astronomy Department, University of Maryland, College Park, MD, USA
| | - Marion Zannese
- Institut d'Astrophysique Spatiale, Université Paris-Saclay CNRS, Orsay, France
| | - Alain Abergel
- Institut d'Astrophysique Spatiale, Université Paris-Saclay CNRS, Orsay, France
| | - Jeronimo Bernard-Salas
- ACRI-ST, Centre dEtudes et de Recherche de Grasse (CERGA), Grasse, France
- INCLASS Common Laboratory, Grasse, France
| | | | - Emeric Bron
- LERMA, Observatoire de Paris, PSL University, Sorbonne Université, CNRS, Meudon, France
| | - Ryan Chown
- Department of Physics and Astronomy, The University of Western Ontario, London, Ontario, Canada
- Institute for Earth and Space Exploration, The University of Western Ontario, London, Ontario, Canada
| | - Sara Cuadrado
- Instituto de Física Fundamental (CSIC), Madrid, Spain
| | - Daniel Dicken
- Institut d'Astrophysique Spatiale, Université Paris-Saclay CNRS, Orsay, France
| | - Meriem Elyajouri
- Institut d'Astrophysique Spatiale, Université Paris-Saclay CNRS, Orsay, France
| | | | - Karl D Gordon
- Space Telescope Science Institute, Baltimore, MD, USA
| | - Lina Issa
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, CNRS, CNES, UPS, Toulouse, France
| | - Olga Kannavou
- Institut d'Astrophysique Spatiale, Université Paris-Saclay CNRS, Orsay, France
| | - Baria Khan
- Department of Physics and Astronomy, The University of Western Ontario, London, Ontario, Canada
| | - Ozan Lacinbala
- KU Leuven Quantum Solid State Physics (QSP), Leuven, Belgium
| | - David Languignon
- LERMA, Observatoire de Paris, PSL University, Sorbonne Université, CNRS, Meudon, France
| | - Romane Le Gal
- Institut de Planétologie et d'Astrophysique de Grenoble, Université Grenoble Alpes, CNRS, Grenoble, France
- Institut de Radioastronomie Millimétrique (IRAM), Saint-Martin d'Hères, France
| | | | - Raphael Meshaka
- LERMA, Observatoire de Paris, PSL University, Sorbonne Université, CNRS, Meudon, France
| | - Yoko Okada
- I. Physikalisches Institut, Universität zu Köln, Cologne, Germany
| | - Takashi Onaka
- Department of Physics, Faculty of Science and Engineering, Meisei University, Tokyo, Japan
- Department of Astronomy, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Sofia Pasquini
- Department of Physics and Astronomy, The University of Western Ontario, London, Ontario, Canada
| | - Marc W Pound
- Astronomy Department, University of Maryland, College Park, MD, USA
| | | | - Markus Röllig
- Physikalischer Verein-Gesellschaft für Bildung und Wissenschaft, Frankfurt, Germany
- Physikalisches Institut, Goethe-Universität, Frankfurt, Germany
| | - Bethany Schefter
- Department of Physics and Astronomy, The University of Western Ontario, London, Ontario, Canada
| | - Thiébaut Schirmer
- Department of Space, Earth, and Environment, Chalmers University of Technology, Onsala Space Observatory, Onsala, Sweden
- Institut d'Astrophysique Spatiale, Université Paris-Saclay CNRS, Orsay, France
| | - Ameek Sidhu
- Department of Physics and Astronomy, The University of Western Ontario, London, Ontario, Canada
- Institute for Earth and Space Exploration, The University of Western Ontario, London, Ontario, Canada
| | - Benoit Tabone
- Institut d'Astrophysique Spatiale, Université Paris-Saclay CNRS, Orsay, France
| | | | - Sílvia Vicente
- Instituto de Astrofísica e Ciências do Espaço, Lisbon, Portugal
| | - Mark G Wolfire
- Astronomy Department, University of Maryland, College Park, MD, USA
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5
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Velilla-Prieto L, Fonfría JP, Agúndez M, Castro-Carrizo A, Guélin M, Quintana-Lacaci G, Cherchneff I, Joblin C, McCarthy MC, Martín-Gago JA, Cernicharo J. Atmospheric molecular blobs shape up circumstellar envelopes of AGB stars. Nature 2023; 617:696-700. [PMID: 37198489 DOI: 10.1038/s41586-023-05917-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 03/02/2023] [Indexed: 05/19/2023]
Abstract
During their thermally pulsing phase, asymptotic giant branch (AGB) stars eject material that forms extended dusty envelopes1. Visible polarimetric imaging found clumpy dust clouds within two stellar radii of several oxygen-rich stars2-6. Inhomogeneous molecular gas has also been observed in multiple emission lines within several stellar radii of different oxygen-rich stars, including W Hya and Mira7-10. At the stellar surface level, infrared images have shown intricate structures around the carbon semiregular variable R Scl and in the S-type star π1 Gru11,12. Infrared images have also shown clumpy dust structures within a few stellar radii of the prototypical carbon AGB star IRC+10°216 (refs. 13,14), and studies of molecular gas distribution beyond the dust formation zone have also shown complex circumstellar structures15. Because of the lack of sufficient spatial resolution, however, the distribution of molecular gas in the stellar atmosphere and the dust formation zone of AGB carbon stars is not known, nor is how it is subsequently expelled. Here we report observations with a resolution of one stellar radius of the recently formed dust and molecular gas in the atmosphere of IRC+10°216. Lines of HCN, SiS and SiC2 appear at different radii and in different clumps, which we interpret as large convective cells in the photosphere, as seen in Betelgeuse16. The convective cells coalesce with pulsation, causing anisotropies that, together with companions17,18, shape its circumstellar envelope.
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Affiliation(s)
- L Velilla-Prieto
- Department of Molecular Astrophysics, Instituto de Física Fundamental, Madrid, Spain.
| | - J P Fonfría
- Centro de Astrobiología, CSIC-INTA, Villanueva de la Cañada, Spain
| | - M Agúndez
- Department of Molecular Astrophysics, Instituto de Física Fundamental, Madrid, Spain
| | - A Castro-Carrizo
- Institut de Radioastronomie Millimétrique, Saint Martin d'Hères, France
| | - M Guélin
- Institut de Radioastronomie Millimétrique, Saint Martin d'Hères, France
| | - G Quintana-Lacaci
- Department of Molecular Astrophysics, Instituto de Física Fundamental, Madrid, Spain
| | - I Cherchneff
- Departement Physik, Universität Basel, Basel, Switzerland
| | - C Joblin
- Institut de Recherche en Astrophysique et Planétologie, Université Toulouse 3 - Paul Sabatier, CNRS, CNES, Toulouse, France
| | - M C McCarthy
- Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, USA
| | - J A Martín-Gago
- Group of Structure of Nanoscopic Systems, Instituto de Ciencia de Materiales de Madrid, Cantoblanco, Spain
| | - J Cernicharo
- Department of Molecular Astrophysics, Instituto de Física Fundamental, Madrid, Spain.
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6
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Garcia GA, Dontot L, Rapacioli M, Spiegelman F, Bréchignac P, Nahon L, Joblin C. Electronic effects in the dissociative ionisation of pyrene clusters. Phys Chem Chem Phys 2023; 25:4501-4510. [PMID: 36722859 DOI: 10.1039/d2cp05679h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We present a combined experimental and theoretical study on the dissociative ionisation of clusters of pyrene. We measured the experimental appearance energies in the photon energy range 7.2-12.0 eV of the fragments formed from neutral monomer loss for clusters up to the hexamer. The results obtained show a deviation from statistical dissociation. From electronic structure calculations, we suggest that the role of excited states must be considered in the interpretation of experimental results, even in these relatively large systems. Non-statistical effects in the dissociative ionization process of polycyclic aromatic hydrocarbon (PAH) clusters may have an impact on the assessment of mechanisms determining the stability of these clusters in astrophysical environments.
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Affiliation(s)
- Gustavo A Garcia
- Synchrotron SOLEIL, L'Orme des Merisiers, Départamentale 128, 91190 Saint Aubin, France.
| | - Léo Dontot
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse III - Paul Sabatier, CNRS, CNES, 9 avenue du Colonel Roche, BP 44346, F-31028 Toulouse, France.,Laboratoire de Chimie et Physique Quantiques, FERMI, Université de Toulouse III - Paul Sabatier, CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
| | - Mathias Rapacioli
- Laboratoire de Chimie et Physique Quantiques, FERMI, Université de Toulouse III - Paul Sabatier, CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
| | - Fernand Spiegelman
- Laboratoire de Chimie et Physique Quantiques, FERMI, Université de Toulouse III - Paul Sabatier, CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
| | - Philippe Bréchignac
- Institut des Sciences Moléculaires d'Orsay, CNRS, Université Paris-Saclay, F-91405 Orsay, France
| | - Laurent Nahon
- Synchrotron SOLEIL, L'Orme des Merisiers, Départamentale 128, 91190 Saint Aubin, France.
| | - Christine Joblin
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse III - Paul Sabatier, CNRS, CNES, 9 avenue du Colonel Roche, BP 44346, F-31028 Toulouse, France
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7
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Banhatti S, Rap DB, Simon A, Leboucher H, Wenzel G, Joblin C, Redlich B, Schlemmer S, Brünken S. Formation of the acenaphthylene cation as a common C 2H 2-loss fragment in dissociative ionization of the PAH isomers anthracene and phenanthrene. Phys Chem Chem Phys 2022; 24:27343-27354. [PMID: 36326610 PMCID: PMC9673687 DOI: 10.1039/d2cp03835h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 10/21/2022] [Indexed: 09/19/2023]
Abstract
Polycyclic aromatic hydrocarbons (PAHs) are thought to be a major constituent of astrophysical environments, being the carriers of the ubiquitous aromatic infrared bands (AIBs) observed in the spectra of galactic and extra-galactic sources that are irradiated by ultraviolet (UV) photons. Small (2-cycles) PAHs were unambiguously detected in the TMC-1 dark cloud, showing that PAH growth pathways exist even at low temperatures. The processing of PAHs by UV photons also leads to their fragmentation, which has been recognized in recent years as an alternative route to the generally accepted bottom-up chemical pathways for the formation of complex hydrocarbons in UV-rich interstellar regions. Here we consider the C12H8+ ion that is formed in our experiments from the dissociative ionization of the anthracene and phenanthrene (C14H10) molecules. By employing the sensitive action spectroscopic scheme of infrared pre-dissociation (IRPD) in a cryogenic ion trap instrument coupled to the free-electron lasers at the FELIX Laboratory, we have recorded the broadband and narrow line-width gas-phase IR spectra of the fragment ions (C12H8+) and also the reference spectra of three low energy isomers of C12H8+. By comparing the experimental spectra to those obtained from quantum chemical calculations we have identified the dominant structure of the fragment ion formed in the dissociation process to be the acenaphthylene cation for both isomeric precursors. Ab initio molecular dynamics simulations are presented to elucidate the fragmentation process. This result reinforces the dominant role of species containing a pentagonal ring in the photochemistry of small PAHs.
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Affiliation(s)
- Shreyak Banhatti
- I. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany.
| | - Daniël B Rap
- Institute for Molecules and Materials, FELIX Laboratory, Radboud University, Toernooiveld 7, 6525 ED, Nijmegen, The Netherlands.
| | - Aude Simon
- Laboratoire de Chimie et Physique Quantiques (LCPQ), Fédération FeRMI, CNRS & Université Toulouse III - Paul Sabatier, 118 Route de Narbonne, 31062 Toulouse, France
| | - Heloïse Leboucher
- Laboratoire de Chimie et Physique Quantiques (LCPQ), Fédération FeRMI, CNRS & Université Toulouse III - Paul Sabatier, 118 Route de Narbonne, 31062 Toulouse, France
| | - Gabi Wenzel
- Center for Interstellar Catalysis (InterCat), Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Aarhus C, Denmark
| | - Christine Joblin
- Institut de Recherche en Astrophysique et Planétologie (IRAP), Université Toulouse III - Paul Sabatier, CNRS, CNES, 9 Avenue du Colonel Roche, 31028 Toulouse, France
| | - Britta Redlich
- Institute for Molecules and Materials, FELIX Laboratory, Radboud University, Toernooiveld 7, 6525 ED, Nijmegen, The Netherlands.
| | - Stephan Schlemmer
- I. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany.
| | - Sandra Brünken
- Institute for Molecules and Materials, FELIX Laboratory, Radboud University, Toernooiveld 7, 6525 ED, Nijmegen, The Netherlands.
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8
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Vinitha MV, Mundlapati VR, Marciniak A, Carlos M, Sabbah H, Bonnamy A, Noguès L, Murat D, Coeur-Joly O, Joblin C. Isomer Differentiation of Trapped C 16H 10+ Using Low-Energy Collisions and Visible/VUV Photons. J Phys Chem A 2022; 126:5632-5646. [PMID: 35951364 DOI: 10.1021/acs.jpca.2c03304] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Polycyclic aromatic hydrocarbons are major species in astrophysical environments, and this motivates their study in samples of astrochemical interest such as meteorites and laboratory analogues of stardust. Molecular analyses of carbonaceous matter in these samples show a dominant peak at m/z = 202.078 corresponding to C16H10. Obtaining information on the associated isomeric structures is a challenge for the molecular analysis of samples available in very small quantities (mg or less). Here we show that coupling laser desorption ionization mass spectrometry with ion trapping opens up the possibility of unraveling isomers by activating ion fragmentation via collisions or photon absorption. We report the best criteria for differentiating isomers with comparable dissociation energies, namely pyrene, fluoranthene, and 9-ethynylphenanthrene, on the basis of the parent dissociation curve and the ratio of dehydrogenation channels. Photoabsorption schemes (multiple photon absorption in the visible range and single photon absorption at 10.5 eV) are more effective in differentiating these isomers than activation by low energy collisions. The impact of the activation scheme on the fragmentation kinetics and dehydrogenation pathways is discussed. By analyzing the 10.5 eV photodissociation measurements with a simple kinetic model, we were able to derive a branching ratio for the H and 2H/H2 loss channels of the parent ions. The results suggest a role in the formation of H2 for bay hydrogens that are present in both fluoranthene and 9-ethynylphenanthrene. In addition, we suggest for the latter the presence of a highly competitive 2H loss channel, possibly associated with the formation of a pentagonal ring.
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Affiliation(s)
- M Viswanathan Vinitha
- Institut de Recherche en Astrophysique et Planétologie (IRAP), Université Toulouse III - Paul Sabatier, CNRS, CNES, 9 Avenue du Colonel Roche, F-31028 Toulouse, France
| | - Venkateswara Rao Mundlapati
- Institut de Recherche en Astrophysique et Planétologie (IRAP), Université Toulouse III - Paul Sabatier, CNRS, CNES, 9 Avenue du Colonel Roche, F-31028 Toulouse, France
| | - Alexandre Marciniak
- Institut de Recherche en Astrophysique et Planétologie (IRAP), Université Toulouse III - Paul Sabatier, CNRS, CNES, 9 Avenue du Colonel Roche, F-31028 Toulouse, France
| | - Mickaël Carlos
- Institut de Recherche en Astrophysique et Planétologie (IRAP), Université Toulouse III - Paul Sabatier, CNRS, CNES, 9 Avenue du Colonel Roche, F-31028 Toulouse, France
| | - Hassan Sabbah
- Institut de Recherche en Astrophysique et Planétologie (IRAP), Université Toulouse III - Paul Sabatier, CNRS, CNES, 9 Avenue du Colonel Roche, F-31028 Toulouse, France
| | - Anthony Bonnamy
- Institut de Recherche en Astrophysique et Planétologie (IRAP), Université Toulouse III - Paul Sabatier, CNRS, CNES, 9 Avenue du Colonel Roche, F-31028 Toulouse, France
| | - Loïc Noguès
- Institut de Recherche en Astrophysique et Planétologie (IRAP), Université Toulouse III - Paul Sabatier, CNRS, CNES, 9 Avenue du Colonel Roche, F-31028 Toulouse, France
| | - David Murat
- Institut de Recherche en Astrophysique et Planétologie (IRAP), Université Toulouse III - Paul Sabatier, CNRS, CNES, 9 Avenue du Colonel Roche, F-31028 Toulouse, France
| | - Odile Coeur-Joly
- Institut de Recherche en Astrophysique et Planétologie (IRAP), Université Toulouse III - Paul Sabatier, CNRS, CNES, 9 Avenue du Colonel Roche, F-31028 Toulouse, France
| | - Christine Joblin
- Institut de Recherche en Astrophysique et Planétologie (IRAP), Université Toulouse III - Paul Sabatier, CNRS, CNES, 9 Avenue du Colonel Roche, F-31028 Toulouse, France
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9
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Abstract
We report measurements of the attachment rates of water molecules onto mass-selected cationic pyrene clusters for size from n = 4 to 13 pyrene units and for different collision energies. Comparison of the attachment rates with the collision rates measured in collision-induced dissociation experiments provides access to the values of the sticking coefficient. The strong dependence of the attachment rates on size and collision energy is rationalized through a model in which we use a Langevin-type collision rate and adjust on experimental data the statistical dissociation rate of the water molecule from the cluster after attachment. This allows us to extrapolate our results to the conditions of isolation and long time scales encountered in astrophysical environments.
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Affiliation(s)
- Sébastien Zamith
- Laboratoire Collision Agrégats Réactivité (LCAR/IRSAMC), UMR5589, Université de Toulouse III - Paul Sabatier and CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
| | - Ali Kassem
- Laboratoire Collision Agrégats Réactivité (LCAR/IRSAMC), UMR5589, Université de Toulouse III - Paul Sabatier and CNRS, 118 Route de Narbonne, F-31062 Toulouse, France.,Institut de Recherche en Astrophysique et Planétologie (IRAP), UMR5277, Université de Toulouse III - Paul Sabatier, CNRS, CNES, 9 avenue du Colonel Roche, F-31028 Toulouse, France
| | - Jean-Marc L'Hermite
- Laboratoire Collision Agrégats Réactivité (LCAR/IRSAMC), UMR5589, Université de Toulouse III - Paul Sabatier and CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
| | - Christine Joblin
- Institut de Recherche en Astrophysique et Planétologie (IRAP), UMR5277, Université de Toulouse III - Paul Sabatier, CNRS, CNES, 9 avenue du Colonel Roche, F-31028 Toulouse, France
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10
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Chakraborty S, Mulas G, Rapacioli M, Joblin C. Anharmonic Infrared Spectra of Thermally Excited Pyrene (C 16H 10): A Combined View of DFT-Based GVPT2 with AnharmonicCaOs, and Approximate DFT Molecular dynamics with DemonNano. J Mol Spectrosc 2021; 378:111466. [PMID: 34257467 PMCID: PMC7611198 DOI: 10.1016/j.jms.2021.111466] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The study of the Aromatic Infrared Bands (AIBs) in astronomical environments has opened interesting spectroscopic questions on the effect of anharmonicity on the infrared (IR) spectrum of hot polycyclic aromatic hydrocarbons (PAHs) and related species in isolated conditions. The forthcoming James Webb Space Telescope will unveil unprecedented spatial and spectral details in the AIB spectrum; significant advancement is thus necessary now to model the infrared emission of PAHs, their presumed carriers, with enough detail to exploit the information content of the AIBs. This requires including anharmonicity in such models, and to do so systematically for all species included, requiring a difficult compromise between accuracy and efficiency. We performed a benchmark study to compare the performances of two methods in calculating anharmonic spectra, comparing them to available experimental data. One is a full quantum method, AnharmoniCaOs, relying on an ab initio potential, and the other relies on Molecular Dynamics simulations using a Density Functional based Tight Binding potential. The first one is found to be very accurate and detailed, but it becomes computationally very expensive for increasing temperature; the second is faster and can be used for arbitrarily high temperatures, but is less accurate. Still, its results can be used to model the evolution with temperature of isolated bands. We propose a new recipe to model anharmonic AIB emission using minimal assumptions on the general behaviour of band positions and widths with temperature, which can be defined by a small number of empirical parameters. Modelling accuracy will depend critically on these empirical parameters, allowing for an incremental improvement in model results, as better estimates become gradually available.
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Affiliation(s)
- Shubhadip Chakraborty
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse (UPS), CNRS, CNES, 9 Av. du Colonel Roche, 31028 Toulouse Cedex 4, France
| | - Giacomo Mulas
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse (UPS), CNRS, CNES, 9 Av. du Colonel Roche, 31028 Toulouse Cedex 4, France
- Istituto Nazionale di Astrofisica (INAF), Osservatorio Astronomico di Cagliari, 09047 Selargius (CA), Italy
| | - Mathias Rapacioli
- Laboratoire de Chimie et Physique Quantiques (LCPQ/IRSAMC), Université de Toulouse (UPS),CNRS, 118 Route de Narbonne, 31062 Toulouse, France
| | - Christine Joblin
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse (UPS), CNRS, CNES, 9 Av. du Colonel Roche, 31028 Toulouse Cedex 4, France
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Jenniskens P, Gabadirwe M, Yin QZ, Proyer A, Moses O, Kohout T, Franchi F, Gibson RL, Kowalski R, Christensen EJ, Gibbs AR, Heinze A, Denneau L, Farnocchia D, Chodas PW, Gray W, Micheli M, Moskovitz N, Onken CA, Wolf C, Devillepoix HAR, Ye Q, Robertson DK, Brown P, Lyytinen E, Moilanen J, Albers J, Cooper T, Assink J, Evers L, Lahtinen P, Seitshiro L, Laubenstein M, Wantlo N, Moleje P, Maritinkole J, Suhonen H, Zolensky ME, Ashwal L, Hiroi T, Sears DW, Sehlke A, Maturilli A, Sanborn ME, Huyskens MH, Dey S, Ziegler K, Busemann H, Riebe MEI, Meier MMM, Welten KC, Caffee MW, Zhou Q, Li QL, Li XH, Liu Y, Tang GQ, McLain HL, Dworkin JP, Glavin DP, Schmitt-Kopplin P, Sabbah H, Joblin C, Granvik M, Mosarwa B, Botepe K. The impact and recovery of asteroid 2018 LA. Meteorit Planet Sci 2021; 56:844-893. [PMID: 34295141 PMCID: PMC7611328 DOI: 10.1111/maps.13653] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 03/23/2021] [Indexed: 06/13/2023]
Abstract
The June 2, 2018, impact of asteroid 2018 LA over Botswana is only the second asteroid detected in space prior to impacting over land. Here, we report on the successful recovery of meteorites. Additional astrometric data refine the approach orbit and define the spin period and shape of the asteroid. Video observations of the fireball constrain the asteroid's position in its orbit and were used to triangulate the location of the fireball's main flare over the Central Kalahari Game Reserve. 23 meteorites were recovered. A consortium study of eight of these classifies Motopi Pan as a HED polymict breccia derived from howardite, cumulate and basaltic eucrite, and diogenite lithologies. Before impact, 2018 LA was a solid rock of ~156 cm diameter with high bulk density ~2.85 g/cm3, a relatively low albedo pv ~ 0.25, no significant opposition effect on the asteroid brightness, and an impact kinetic energy of ~0.2 kt. The orbit of 2018 LA is consistent with an origin at Vesta (or its Vestoids) and delivery into an Earth-impacting orbit via the v6 resonance. The impact that ejected 2018 LA in an orbit towards Earth occurred 22.8 ± 3.8 Ma ago. Zircons record a concordant U-Pb age of 4563 ± 11 Ma and a consistent 207Pb/206Pb age of 4563 ± 6 Ma. A much younger Pb-Pb phosphate resetting age of 4234 ± 41 Ma was found. From this impact chronology, we discuss what is the possible source crater of Motopi Pan and the age of Vesta's Veneneia impact basin.
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Affiliation(s)
- Peter Jenniskens
- SETI Institute, 189 Bernardo Avenue, Mountain View, CA 94043, USA
- NASA Ames Research Center, Moffett Field, CA 94035, USA
| | - Mohutsiwa Gabadirwe
- Botswana Geoscience Institute, Plot 11566, Khama 1 Avenue, Private Bag 0014, Lobatse, Botswana
| | - Qing-Zhu Yin
- Department of Earth and Planetary Sciences, University of California Davis, One Shields Avenue, CA 95616, USA
| | - Alexander Proyer
- Botswana International University of Science and Technology, Private Bag 16, Palapye, Botswana
| | - Oliver Moses
- University of Botswana, Okavango Research Institute, Private Bag 285, Maun, Botswana
| | - Tomas Kohout
- Department of Geosciences and Geography, University of Helsinki, P. O. Box 64, FI-00014 Helsinki, Finland
- Ursa Finnish Fireball Network, Kopernikuksentie 1, FI-00130 Helsinki, Finland
| | - Fulvio Franchi
- Botswana International University of Science and Technology, Private Bag 16, Palapye, Botswana
| | - Roger L. Gibson
- School of Geosciences, University of the Witwatersrand, P.O. WITS, Johannesburg 2050, South Africa
| | - Richard Kowalski
- Catalina Sky Survey, Lunar & Planetary Laboratory, The University of Arizona, 1629 E University Blvd., Tucson, AZ 85721, USA
| | - Eric J. Christensen
- Catalina Sky Survey, Lunar & Planetary Laboratory, The University of Arizona, 1629 E University Blvd., Tucson, AZ 85721, USA
| | - Alex R. Gibbs
- Catalina Sky Survey, Lunar & Planetary Laboratory, The University of Arizona, 1629 E University Blvd., Tucson, AZ 85721, USA
| | - Aren Heinze
- ATLAS, Institute for Astronomy, 2680 Woodlawn Drive, Honolulu, HI 96822-1839, USA
| | - Larry Denneau
- ATLAS, Institute for Astronomy, 2680 Woodlawn Drive, Honolulu, HI 96822-1839, USA
| | - Davide Farnocchia
- Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
| | - Paul W. Chodas
- Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
| | - William Gray
- Project Pluto, 168 Ridge Road, Bowdoinham, ME 04008, USA
| | - Marco Micheli
- ESA NEO Coordination Centre, Largo Galileo Galilei 1, I-00044, Frascati, Italy
| | - Nick Moskovitz
- Lowell Observatory, 1400 W. Mars Hill Rd., Flagstaff, AZ 86001, USA
| | - Christopher A. Onken
- Research School of Astronomy and Astrophysics, The Australian National University, Canberra ACT 2611, Australia
| | - Christian Wolf
- Research School of Astronomy and Astrophysics, The Australian National University, Canberra ACT 2611, Australia
| | | | - Quanzhi Ye
- Department of Astronomy, University of Maryland, College Park, MD 20742, USA
- Division of Physics, Mathematics and Astronomy, Caltech, Pasadena, CA 91125, USA
| | - Darrel K. Robertson
- NASA Ames Research Center, Asteroid Threat Assessment Project, Mail Stop 239-1, Moffett Field, CA 94035, USA
| | - Peter Brown
- Centre for Planetary Science and Exploration, Western University, London, Ontario, N6A 5B7, Canada
| | - Esko Lyytinen
- Ursa Finnish Fireball Network, Kopernikuksentie 1, FI-00130 Helsinki, Finland
| | - Jarmo Moilanen
- Ursa Finnish Fireball Network, Kopernikuksentie 1, FI-00130 Helsinki, Finland
| | - Jim Albers
- SETI Institute, 189 Bernardo Avenue, Mountain View, CA 94043, USA
| | - Tim Cooper
- Astronomical Society of Southern Africa, Suite 617, Private Bag X043, Benoni 1500, South Africa
| | - Jelle Assink
- Royal Dutch Meteorological Institute, R&D Seismology and Acoustics, P. O. Box 201, NL-3730 AE De Bilt, The Netherlands
| | - Läslo Evers
- Royal Dutch Meteorological Institute, R&D Seismology and Acoustics, P. O. Box 201, NL-3730 AE De Bilt, The Netherlands
- Delft University of Technology, Department of Geoscience and Engineering, P. O. Box 5048, NL-2600 GA Delft, the Netherlands
| | - Panu Lahtinen
- Ursa Finnish Fireball Network, Kopernikuksentie 1, FI-00130 Helsinki, Finland
| | - Lesedi Seitshiro
- Botswana International University of Science and Technology, Private Bag 16, Palapye, Botswana
| | - Matthias Laubenstein
- Gran Sasso National Laboratory, National Institute for Nuclear Physics, Via G. Acitelli 22, I-67100 Assergi, Italy
| | - Nggie Wantlo
- Botswana Geoscience Institute, Plot 11566, Khama 1 Avenue, Private Bag 0014, Lobatse, Botswana
| | - Phemo Moleje
- Botswana Geoscience Institute, Plot 11566, Khama 1 Avenue, Private Bag 0014, Lobatse, Botswana
| | - Joseph Maritinkole
- Botswana Geoscience Institute, Plot 11566, Khama 1 Avenue, Private Bag 0014, Lobatse, Botswana
| | - Heikki Suhonen
- University of Helsinki, Department of Physics, P. O. Box 64, FI-00014 Helsinki, Finland
| | | | - Lewis Ashwal
- School of Geosciences, University of the Witwatersrand, P.O. WITS, Johannesburg 2050, South Africa
| | - Takahiro Hiroi
- Brown University, Reflectance Experiment Laboratory, Department of Earth, Environmental and Planetary Science, Providence, RI 02912, USA
| | - Derek W. Sears
- NASA Ames Research Center / Bay Area Environmental Research Institute, Mail Stop 245-3, Moffett Field, CA 94035, USA
| | - Alexander Sehlke
- NASA Ames Research Center / Bay Area Environmental Research Institute, Mail Stop 245-3, Moffett Field, CA 94035, USA
| | - Alessandro Maturilli
- Institute for Planetary Research, German Aerospace Center DLR, Rutherfordstrasse 2, D-12489 Berlin-Adlershof, Germany
| | - Matthew E. Sanborn
- Department of Earth and Planetary Sciences, University of California Davis, One Shields Avenue, CA 95616, USA
| | - Magdalena H. Huyskens
- Department of Earth and Planetary Sciences, University of California Davis, One Shields Avenue, CA 95616, USA
| | - Supratim Dey
- Department of Earth and Planetary Sciences, University of California Davis, One Shields Avenue, CA 95616, USA
| | - Karen Ziegler
- University of New Mexico, Institute of Meteoritics, 221 Yale Blvd NE, 331 Northrop Hall, Albuquerque, NM 87131, USA
| | - Henner Busemann
- Institute of Geochemistry and Petrology, ETH Zürich, Clausiusstrasse 25, CH-8092 Zürich, Switzerland
| | - My E. I. Riebe
- Institute of Geochemistry and Petrology, ETH Zürich, Clausiusstrasse 25, CH-8092 Zürich, Switzerland
| | - Matthias M. M. Meier
- Naturmuseum St. Gallen, Rorschacher Strasse 263, CH-9016 St. Gallen, Switzerland
| | - Kees C. Welten
- University of California Berkeley, Space Science Laboratory, Berkeley, CA 94720, USA
| | - Marc W. Caffee
- Purdue University, Dept. Physics and Astronomy, 525 Northwestern Avenue, West Lafayette, IN 47907, USA
| | - Qin Zhou
- National Astronomical Observatories, Beijing, Chinese Academy of Sciences, Beijing 100012, China
| | - Qiu-Li Li
- National Astronomical Observatories, Beijing, Chinese Academy of Sciences, Beijing 100012, China
| | - Xian-Hua Li
- State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
| | - Yu Liu
- State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
| | - Guo-Qiang Tang
- State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
| | - Hannah L. McLain
- Catholic University of America, Department of Chemistry, 620 Michigan Ave, N.E., Washington, DC 20064, USA
- NASA Goddard Space Flight Center, 8800 Greenbelt Rd., Greenbelt, MD 20771, USA
| | - Jason P. Dworkin
- NASA Goddard Space Flight Center, 8800 Greenbelt Rd., Greenbelt, MD 20771, USA
| | - Daniel P. Glavin
- NASA Goddard Space Flight Center, 8800 Greenbelt Rd., Greenbelt, MD 20771, USA
| | - Philippe Schmitt-Kopplin
- Helmholtz Zentrum München, Research Unit Analytical BioGeoChemistry, Ingolstädter Landstr. 1, D-85764 Neuherberg, Germany
- Technische Universität München, Analytical Food Chemistry, D-85354 Freising-Weihenstephan, Germany
| | - Hassan Sabbah
- IRAP, Université de Toulouse, CNRS, CNES, Université de Toulouse (UPS), F-31028 Toulouse Cedex 4, France
| | | | - Mikael Granvik
- University of Helsinki, Department of Physics, P. O. Box 64, FI-00014 Helsinki, Finland
- Asteroid Engineering Laboratory, Onboard Space Systems, Lulea University of Technology, Box 848, S-981 28 Kiruna, Sweden
| | - Babutsi Mosarwa
- Botswana National Museum, 161 Queens Rd., Gaborone, Botswana
| | - Koketso Botepe
- Botswana Geoscience Institute, Plot 11566, Khama 1 Avenue, Private Bag 0014, Lobatse, Botswana
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12
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Bérard R, Makasheva K, Demyk K, Simon A, Reyes DN, Mastrorocco F, Sabbah H, Joblin C. Impact of metals on (star)dust chemistry: a laboratory astrophysics approach. Front Astron Space Sci 2021; 8:654879. [PMID: 33850840 PMCID: PMC7610582 DOI: 10.3389/fspas.2021.654879] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Laboratory experiments are essential in exploring the mechanisms involved in stardust formation. One key question is how a metal is incorporated into dust for an environment rich in elements involved in stardust formation (C, H, O, Si). To address experimentally this question we have used a radiofrequency cold plasma reactor in which cyclic organosilicon dust formation is observed. Metallic (silver) atoms were injected in the plasma during the dust nucleation phase to study their incorporation in the dust. The experiments show formation of silver nanoparticles (~15 nm) under conditions in which organosilicon dust of size 200 nm or less is grown. The presence of AgSiO bonds, revealed by infrared spectroscopy, suggests the presence of junctions between the metallic nanoparticles and the organosilicon dust. Even after annealing we could not conclude on the formation of silver silicates, emphasizing that most of silver is included in the metallic nanoparticles. The molecular analysis performed by laser mass spectrometry exhibits a complex chemistry leading to a variety of molecules including large hydrocarbons and organometallic species. In order to gain insights into the involved chemical molecular pathways, the reactivity of silver atoms/ions with acetylene was studied in a laser vaporization source. Key organometallic species, Ag n C2H m (n=1-3; m=0-2), were identified and their structures and energetic data computed using density functional theory. This allows us to propose that molecular Ag-C seeds promote the formation of Ag clusters but also catalyze hydrocarbon growth. Throughout the article, we show how the developed methodology can be used to characterize the incorporation of metal atoms both in the molecular and dust phases. The presence of silver species in the plasma was motivated by objectives finding their application in other research fields than astrochemistry. Still, the reported methodology is a demonstration laying down the ground for future studies on metals of astrophysical interest such as iron.
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Affiliation(s)
- Rémi Bérard
- IRAP, Université de Toulouse, CNRS, UPS, CNES, TOULOUSE, France
- LAPLACE, Université de Toulouse, CNRS, UPS, INPT, TOULOUSE, France
| | | | - Karine Demyk
- IRAP, Université de Toulouse, CNRS, UPS, CNES, TOULOUSE, France
| | - Aude Simon
- LCPQ-IRSAMC, Université de Toulouse, UPS, CNRS, TOULOUSE, France
| | | | | | - Hassan Sabbah
- IRAP, Université de Toulouse, CNRS, UPS, CNES, TOULOUSE, France
- LCAR-IRSAMC, Université de Toulouse, UPS, CNRS, TOULOUSE, France
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Bernard J, Al-Mogeeth A, Martin S, Montagne G, Joblin C, Dontot L, Spiegelman F, Rapacioli M. Experimental and theoretical study of photo-dissociation spectroscopy of pyrene dimer radical cations stored in a compact electrostatic ion storage ring. Phys Chem Chem Phys 2021; 23:6017-6028. [PMID: 33667290 DOI: 10.1039/d0cp05779g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this paper, we present an experimental and theoretical study of the photo-dissociation of free-flying dimer radical cations of pyrene (C16H10)2+. Experimentally, the dimers were produced in the plasma of an electron cyclotron resonance ion source and stored in an electrostatic ion storage ring, the Mini-Ring for times up to 10 ms and the photo-dissociation spectrum was recorded in the 400 to 2000 nm range. Two broad absorption bands were observed at 550 (2.25 eV) and 1560 nm (0.79 eV), respectively. Theoretical simulations of the absorption spectrum as a function of the temperature were performed using the Density Functional based Tight Binding approach within the Extended Configuration Interaction scheme (DFTB-EXCI) to determine the electronic structure. The simulation involved all excited electronic states correlated asymptotically with the five lowest excited states D1-D5 of the monomer cation and a Monte Carlo exploration of the electronic ground state potential energy surface. The simulations exhibit three major bands at 1.0, 2.1 and 2.8 eV respectively. They allow assigning the experimental band at 1560 nm to absorption by the charge resonance (CR) excited state correlated with the ground state of the monomer D0. The band at 550 nm is tentatively attributed to dimer states correlated with excited states D2-D4, in the monomer cation. Simulations also show that the CR band broadens and shifts towards longer wavelength with increasing temperature. It results from the dependence on the geometry of the energy gap between the ground state and the lowest excited state. The comparison of the experimental spectrum with theoretical spectra at various temperatures allows us to estimate the temperature of the stored (C16H10)2+ in the 300-400 K range, which is also in line with the expected temperatures of the ions deduced from the analysis of the natural decay curve.
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Affiliation(s)
- J Bernard
- Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne cedex, France.
| | - A Al-Mogeeth
- Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne cedex, France.
| | - S Martin
- Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne cedex, France.
| | - G Montagne
- Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne cedex, France.
| | - C Joblin
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse (UPS), CNRS, CNES, 9 Avenue du Colonel Roche, F-31028 Toulouse, France
| | - L Dontot
- Laboratoire de Chimie et de Physique Quantiques (LCPQ), IRSAMC, Université de Toulouse (UPS) and CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
| | - F Spiegelman
- Laboratoire de Chimie et de Physique Quantiques (LCPQ), IRSAMC, Université de Toulouse (UPS) and CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
| | - M Rapacioli
- Laboratoire de Chimie et de Physique Quantiques (LCPQ), IRSAMC, Université de Toulouse (UPS) and CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
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Sabbah H, Commodo M, Picca F, De Falco G, Minutolo P, D’Anna A, Joblin C. Molecular content of nascent soot: Family characterization using two-step laser desorption laser ionization mass spectrometry. Proc Combust Inst 2020; 38:1241-1248. [PMID: 33850480 PMCID: PMC7610591 DOI: 10.1016/j.proci.2020.09.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Molecules constituting nascent soot particles have been analyzed by two-step laser desorption laser ionization mass spectrometry. Three samples have been collected from a slightly sooting ethylene/air premixed flame with the aim to investigate soot composition in the transition from nucleated to just-grown soot particles. Sampling locations have been selected based on the evolution of the particle size distribution along the flame axis. The mass spectrometric results point to a strong evolution of the molecular composition. Just-nucleated soot is rich in polycyclic aromatic hydrocarbons (PAHs) dominated by medium sizes from 18 to 40 carbon atoms but containing sizes as large as 90 carbon atoms. Most abundant PAHs are in the form of peri-condensed structures. The presence of a large fraction of odd numbered carbon species shows that pentagonal cycles are a common feature of the detected population. Increasing the distance from the burner outlet, i.e., the particle residence time in flame, leads to an evolution of the chemical composition of this population with a major contribution of carbon clusters including also fullerenes up to about 160 carbon atoms. Our data support a scenario in which large PAHs containing pentagonal rings evolve very efficiently upon thermal processing by a series of dehydrogenation and isomerization processes to form fullerenes. This chemistry happens in the early steps of soot growth showing that carbonization is already active at this stage. © 2020 The Authors. Published by Elsevier Inc. on behalf of The Combustion Institute. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
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Affiliation(s)
- Hassan Sabbah
- Institut de Recherche en Astrophysique et Planétologie
(IRAP), Université de Toulouse (UPS), CNRS, CNES, 9 Av. du Colonel Roche,
31028 Toulouse Cedex 4, France
| | - Mario Commodo
- Istituto di Ricerche sulla Combustione, CNR, P.le Tecchio 80, 80125
Napoli, Italy
| | - Francesca Picca
- Dipartimento di Ingegneria Chimica, dei Materiali e della Produzione
Industriale - Università degli Studi di Napoli Federico II, P.le Tecchio 80,
80125 Napoli, Italy
| | - Gianluigi De Falco
- Dipartimento di Ingegneria Chimica, dei Materiali e della Produzione
Industriale - Università degli Studi di Napoli Federico II, P.le Tecchio 80,
80125 Napoli, Italy
| | - Patrizia Minutolo
- Istituto di Ricerche sulla Combustione, CNR, P.le Tecchio 80, 80125
Napoli, Italy
| | - Andrea D’Anna
- Dipartimento di Ingegneria Chimica, dei Materiali e della Produzione
Industriale - Università degli Studi di Napoli Federico II, P.le Tecchio 80,
80125 Napoli, Italy
| | - Christine Joblin
- Institut de Recherche en Astrophysique et Planétologie
(IRAP), Université de Toulouse (UPS), CNRS, CNES, 9 Av. du Colonel Roche,
31028 Toulouse Cedex 4, France
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15
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Wenzel G, Joblin C, Giuliani A, Rodriguez Castillo S, Mulas G, Ji M, Sabbah H, Quiroga S, Peña D, Nahon L. Astrochemical relevance of VUV ionization of large PAH cations . Astron Astrophys 2020; 641:A98. [PMID: 33154599 PMCID: PMC7116310 DOI: 10.1051/0004-6361/202038139] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
CONTEXT As a part of interstellar dust, polycyclic aromatic hydrocarbons (PAHs) are processed by the interaction with vacuum ultra-violet (VUV) photons that are emitted by hot young stars. This interaction leads to the emission of the well-known aromatic infrared bands but also of electrons, which can significantly contribute to the heating of the interstellar gas. AIMS Our aim is to investigate the impact of molecular size on the photoionization properties of cationic PAHs. METHODS Trapped PAH cations of sizes between 30 and 48 carbon atoms were submitted to VUV photons in the range of 9 to 20 eV from the DESIRS beamline at the synchrotron SOLEIL. All resulting photoproducts including dications and fragment cations were mass-analyzed and recorded as a function of photon energy. RESULTS Photoionization is found to be predominant over dissociation at all energies, which differs from an earlier study on smaller PAHs. The photoionization branching ratio reaches 0.98 at 20 eV for the largest studied PAH. The photoionization threshold is observed to be between 9.1 and 10.2 eV, in agreement with the evolution of the ionization potential with size. Ionization cross sections were indirectly obtained and photoionization yields extracted from their ratio with theoretical photoabsorption cross sections, which were calculated using time-dependent density functional theory. An analytical function was derived to calculate this yield for a given molecular size. CONCLUSIONS Large PAH cations could be efficiently ionized in H i regions and provide a contribution to the heating of the gas by photoelectric effect. Also, at the border of or in H ii regions, PAHs could be exposed to photons of energy higher than 13.6 eV. Our work provides recipes to be used in astronomical models to quantify these points.
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Affiliation(s)
- G. Wenzel
- Institut de Recherche en Astrophysique et Planétologie (IRAP), Université de Toulouse (UPS), CNRS, CNES, 9 Avenue du Colonel Roche, F-31028 Toulouse, France
| | - C. Joblin
- Institut de Recherche en Astrophysique et Planétologie (IRAP), Université de Toulouse (UPS), CNRS, CNES, 9 Avenue du Colonel Roche, F-31028 Toulouse, France
| | - A. Giuliani
- Synchrotron SOLEIL, L’Orme des Merisiers, F-91192 Saint Aubin, Gif-sur-Yvette, France
- INRAE, UAR1008, Transform Department, Rue de la Géraudière, BP 71627, F-44316 Nantes, France
| | - S. Rodriguez Castillo
- Institut de Recherche en Astrophysique et Planétologie (IRAP), Université de Toulouse (UPS), CNRS, CNES, 9 Avenue du Colonel Roche, F-31028 Toulouse, France
- Laboratoire de Chimie et Physique Quantiques (LCPQ/IRSAMC), Université de Toulouse (UPS), CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
| | - G. Mulas
- Institut de Recherche en Astrophysique et Planétologie (IRAP), Université de Toulouse (UPS), CNRS, CNES, 9 Avenue du Colonel Roche, F-31028 Toulouse, France
- Istituto Nazionale di Astrofisica – Osservatorio Astronomico di Cagliari, Via della Scienza 5, I-09047 Selargius (CA), Italy
| | - M. Ji
- Institut de Recherche en Astrophysique et Planétologie (IRAP), Université de Toulouse (UPS), CNRS, CNES, 9 Avenue du Colonel Roche, F-31028 Toulouse, France
| | - H. Sabbah
- Institut de Recherche en Astrophysique et Planétologie (IRAP), Université de Toulouse (UPS), CNRS, CNES, 9 Avenue du Colonel Roche, F-31028 Toulouse, France
- Laboratoire Collisions Agrégats Réactivité (LCAR/IRSAMC), Université de Toulouse (UPS), CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
| | - S. Quiroga
- Centro de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS) and Departamento de Química Orgánica, Universidade de Santiago de Compostela, E-15782 Santiago de Compostela, Spain
| | - D. Peña
- Centro de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS) and Departamento de Química Orgánica, Universidade de Santiago de Compostela, E-15782 Santiago de Compostela, Spain
| | - L. Nahon
- Synchrotron SOLEIL, L’Orme des Merisiers, F-91192 Saint Aubin, Gif-sur-Yvette, France
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Zamith S, L’Hermite JM, Dontot L, Zheng L, Rapacioli M, Spiegelman F, Joblin C. Threshold collision induced dissociation of pyrene cluster cations. J Chem Phys 2020; 153:054311. [PMID: 32770931 PMCID: PMC7116296 DOI: 10.1063/5.0015385] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We report threshold collision induced dissociation experiments on cationic pyrene clusters, for sizes n = 2-6. Fragmentation cross sections are recorded as a function of the collision energy and analyzed with a statistical model. This model can account for the dissociation cascades and provides values for the dissociation energies. These values, of the order of 0.7 eV-1 eV, are in excellent agreement with those previously derived from thermal evaporation. They confirm the charge resonance stability enhancement predicted by theoretical calculations. In addition, remarkable agreement is obtained with theoretical predictions for the two smaller sizes n = 2 and 3. For the larger sizes, the agreement remains good, although the theoretical values obtained for the most stable structures are systematically higher by 0.2 eV. This offset could be attributed to approximations in the calculations. Still, there is an indication in the results of an incomplete description of the role of isomerization and/or direct dissociation upon collisions. Finally, by-product clusters containing dehydrogenated species are found to dissociate at energies comparable to the non-dehydrogenated ones, which shows no evidence for covalent bonds within the clusters.
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Affiliation(s)
- Sébastien Zamith
- Laboratoire Collision Agrégats Réactivité (LCAR/IRSAMC), UMR5589, Université de Toulouse (UPS) and CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
| | - Jean-Marc L’Hermite
- Laboratoire Collision Agrégats Réactivité (LCAR/IRSAMC), UMR5589, Université de Toulouse (UPS) and CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
| | - Léo Dontot
- Laboratoire de Chimie et Physique Quantique (LCPQ/IRSAMC), UMR5626, Université de Toulouse (UPS) and CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
| | - Linjie Zheng
- Laboratoire de Chimie et Physique Quantique (LCPQ/IRSAMC), UMR5626, Université de Toulouse (UPS) and CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
| | - Mathias Rapacioli
- Laboratoire de Chimie et Physique Quantique (LCPQ/IRSAMC), UMR5626, Université de Toulouse (UPS) and CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
| | - Fernand Spiegelman
- Laboratoire de Chimie et Physique Quantique (LCPQ/IRSAMC), UMR5626, Université de Toulouse (UPS) and CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
| | - Christine Joblin
- Institut de Recherche en Astrophysique et Planétologie (IRAP), UMR5277, Université de Toulouse (UPS) and CNRS, 9 avenue du Colonel Roche, F-31028 Toulouse, France
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17
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Santoro G, Martínez L, Lauwaet K, Accolla M, Tajuelo-Castilla G, Merino P, Sobrado JM, Peláez RJ, Herrero VJ, Tanarro I, Mayoral ÁL, Agúndez M, Sabbah H, Joblin C, Cernicharo J, Martín-Gago JÁ. The Chemistry of Cosmic Dust Analogues from C, C 2, and C 2H 2 in C-Rich Circumstellar Envelopes. Astrophys J 2020; 895:97. [PMID: 33154601 PMCID: PMC7116318 DOI: 10.3847/1538-4357/ab9086] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Interstellar carbonaceous dust is mainly formed in the innermost regions of circumstellar envelopes around carbon-rich asymptotic giant branch (AGB) stars. In these highly chemically stratified regions, atomic and diatomic carbon, along with acetylene are the most abundant species after H2 and CO. In a previous study, we addressed the chemistry of carbon (C and C2) with H2 showing that acetylene and aliphatic species form efficiently in the dust formation region of carbon-rich AGBs whereas aromatics do not. Still, acetylene is known to be a key ingredient in the formation of linear polyacetylenic chains, benzene and polycyclic aromatic hydrocarbons (PAHs), as shown by previous experiments. However, these experiments have not considered the chemistry of carbon (C and C2) with C2H2. In this work, by employing a sufficient amount of acetylene, we investigate its gas-phase interaction with atomic and diatomic carbon. We show that the chemistry involved produces linear polyacetylenic chains, benzene and other PAHs, which are observed with high abundances in the early evolutionary phase of planetary nebulae. More importantly, we have found a non-negligible amount of pure and hydrogenated carbon clusters as well as aromatics with aliphatic substitutions, both being a direct consequence of the addition of atomic carbon. The incorporation of alkyl substituents into aromatics can be rationalized by a mechanism involving hydrogen abstraction followed by methyl addition. All the species detected in gas phase are incorporated into the nanometric sized dust analogues, which consist of a complex mixture of sp, sp2 and sp3 hydrocarbons with amorphous morphology.
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Affiliation(s)
- Gonzalo Santoro
- Instituto de Ciencia de Materiales de Madrid (ICMM. CSIC). Materials Science Factory. Structure of Nanoscopic Systems Group. c/ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Madrid, Spain
| | - Lidia Martínez
- Instituto de Ciencia de Materiales de Madrid (ICMM. CSIC). Materials Science Factory. Structure of Nanoscopic Systems Group. c/ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Madrid, Spain
| | - Koen Lauwaet
- IMDEA Nanociencia. Ciudad Universitaria de Cantoblanco, 28049 Cantoblanco, Madrid, Spain
| | - Mario Accolla
- Instituto de Ciencia de Materiales de Madrid (ICMM. CSIC). Materials Science Factory. Structure of Nanoscopic Systems Group. c/ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Madrid, Spain
| | - Guillermo Tajuelo-Castilla
- Instituto de Ciencia de Materiales de Madrid (ICMM. CSIC). Materials Science Factory. Structure of Nanoscopic Systems Group. c/ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Madrid, Spain
| | - Pablo Merino
- Instituto de Ciencia de Materiales de Madrid (ICMM. CSIC). Materials Science Factory. Structure of Nanoscopic Systems Group. c/ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Madrid, Spain
- Instituto de Física Fundamental (IFF. CSIC). Group of Molecular Astrophysics. c/ Serrano 123, 28006 Madrid, Spain
| | - Jesús M. Sobrado
- Centro de Astrobiología (CAB. INTA-CSIC). Crta- de Torrejón a Ajalvir km4, 28850, Torrejón de Ardoz, Madrid, Spain
| | - Ramón J. Peláez
- Instituto de Estructura de la Materia (IEM.CSIC). Molecular Physics Department. c/Serrano 123, 28006 Madrid, Spain
| | - Víctor J. Herrero
- Instituto de Estructura de la Materia (IEM.CSIC). Molecular Physics Department. c/Serrano 123, 28006 Madrid, Spain
| | - Isabel Tanarro
- Instituto de Estructura de la Materia (IEM.CSIC). Molecular Physics Department. c/Serrano 123, 28006 Madrid, Spain
| | - Á lvaro Mayoral
- School of Physical Science and Technology, ShanghaiTech University, 393 Middle Huaxia Road, Pudong, Shanghai, 201210, Peoples Republic of China
| | - Marcelino Agúndez
- Instituto de Física Fundamental (IFF. CSIC). Group of Molecular Astrophysics. c/ Serrano 123, 28006 Madrid, Spain
| | - Hassan Sabbah
- IRAP, Université de Toulouse, CNRS, CNES. 9 Av. du Colonel Roche, 31028 Toulouse Cedex 4, France
| | - Christine Joblin
- IRAP, Université de Toulouse, CNRS, CNES. 9 Av. du Colonel Roche, 31028 Toulouse Cedex 4, France
| | - José Cernicharo
- Instituto de Física Fundamental (IFF. CSIC). Group of Molecular Astrophysics. c/ Serrano 123, 28006 Madrid, Spain
| | - José Ángel Martín-Gago
- Instituto de Ciencia de Materiales de Madrid (ICMM. CSIC). Materials Science Factory. Structure of Nanoscopic Systems Group. c/ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Madrid, Spain
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Martínez L, Santoro G, Merino P, Accolla M, Lauwaet K, Sobrado J, Sabbah H, Pelaez RJ, Herrero VJ, Tanarro I, Agúndez M, Martín-Jimenez A, Otero R, Ellis GJ, Joblin C, Cernicharo J, Martín-Gago JA. Prevalence of non-aromatic carbonaceous molecules in the inner regions of circumstellar envelopes. Nat Astron 2020; 4:97-105. [PMID: 31934643 PMCID: PMC6957349 DOI: 10.1038/s41550-019-0899-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 08/27/2019] [Indexed: 05/29/2023]
Abstract
Evolved stars are a foundry of chemical complexity, gas and dust that provides the building blocks of planets and life, and dust nucleation first occurs in their photosphere. Despite their importance, the circumstellar regions enveloping these stars remain hidden to many observations, thus dust formation processes are still poorly understood. Laboratory astrophysics provides complementary routes to unveil these chemical processes, but most experiments rely on combustion or plasma decomposition of molecular precursors under physical conditions far removed from those in space. We have built an ultra-high vacuum machine combining atomic gas aggregation with advanced in-situ characterization techniques to reproduce and characterize the bottom-up dust formation process. We show that carbonaceous dust analogues formed from low-pressure gas-phase condensation of C atoms in a hydrogen atmosphere, in a C/H2 ratio similar to that reported for evolved stars, leads to the formation of amorphous C nanograins and aliphatic C-clusters. Aromatic species or fullerenes do not form effectively under these conditions, raising implications for the revision of the chemical mechanisms taking place in circumstellar envelopes.
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Affiliation(s)
- Lidia Martínez
- Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC). Structure of Nanoscopic Systems Group. C/Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Madrid, Spain
| | - Gonzalo Santoro
- Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC). Structure of Nanoscopic Systems Group. C/Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Madrid, Spain
| | - Pablo Merino
- Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC). Structure of Nanoscopic Systems Group. C/Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Madrid, Spain
- Instituto de Física Fundamental (IFF-CSIC). Group of Molecular Astrophysics, C/Serrano 123, 28006 Madrid, Spain
| | - Mario Accolla
- Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC). Structure of Nanoscopic Systems Group. C/Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Madrid, Spain
| | - Koen Lauwaet
- IMDEA Nanociencia, Ciudad Universitaria de Cantoblanco, 28049 Cantoblanco, Madrid, Spain
| | - Jesús Sobrado
- Centro de Astrobiología (CAB, INTA-CSIC). Crtade Torrejon a Ajalvir km4, 28850 Torrejon de Ardoz, Madrid, Spain
| | - Hassan Sabbah
- IRAP, Université de Toulouse, CNRS, CNES, 9 Av. du Colonel Roche, 31028 Toulouse Cedex 4, France
| | - Ramón J. Pelaez
- Instituto de Estructura de la Materia (IEM-CSIC). Molecular Physics Department. C/Serrano 123, 28006 Madrid, Spain
| | - Victor J. Herrero
- Instituto de Estructura de la Materia (IEM-CSIC). Molecular Physics Department. C/Serrano 123, 28006 Madrid, Spain
| | - Isabel Tanarro
- Instituto de Estructura de la Materia (IEM-CSIC). Molecular Physics Department. C/Serrano 123, 28006 Madrid, Spain
| | - Marcelino Agúndez
- Instituto de Física Fundamental (IFF-CSIC). Group of Molecular Astrophysics, C/Serrano 123, 28006 Madrid, Spain
| | - Alberto Martín-Jimenez
- IMDEA Nanociencia, Ciudad Universitaria de Cantoblanco, 28049 Cantoblanco, Madrid, Spain
| | - Roberto Otero
- IMDEA Nanociencia, Ciudad Universitaria de Cantoblanco, 28049 Cantoblanco, Madrid, Spain
| | - Gary J. Ellis
- Instituto de Ciencia y Tecnología de Polímeros (ICTP-CSIC). C/Juan de la Cierva 3, 28006 Madrid, Spain
| | - Christine Joblin
- IRAP, Université de Toulouse, CNRS, CNES, 9 Av. du Colonel Roche, 31028 Toulouse Cedex 4, France
| | - José Cernicharo
- Instituto de Física Fundamental (IFF-CSIC). Group of Molecular Astrophysics, C/Serrano 123, 28006 Madrid, Spain
| | - José A. Martín-Gago
- Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC). Structure of Nanoscopic Systems Group. C/Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Madrid, Spain
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Abstract
CONTEXT The James Webb Space Telescope (JWST) will deliver an unprecedented quantity of high-quality spectral data over the 0.6-28 μm range. It will combine sensitivity, spectral resolution, and spatial resolution. Specific tools are required to provide efficient scientific analysis of such large data sets. AIMS Our aim is to illustrate the potential of unsupervised learning methods to get insights into chemical variations in the populations that carry the aromatic infrared bands (AIBs), more specifically polycyclic aromatic hydrocarbon (PAH) species and carbonaceous very small grains (VSGs). METHODS We present a method based on linear fitting and blind signal separation for extracting representative spectra for a spectral data set. The method is fast and robust, which ensures its applicability to JWST spectral cubes. We tested this method on a sample of ISO-SWS data, which resemble most closely the JWST spectra in terms of spectral resolution and coverage. RESULTS Four representative spectra were extracted. Their main characteristics appear consistent with previous studies with populations dominated by cationic PAHs, neutral PAHs, evaporating VSGs, and large ionized PAHs, known as the PAH x population. In addition, the 3 μm range, which is considered here for the first time in a blind signal separation (BSS) method, reveals the presence of aliphatics connected to neutral PAHs. Each representative spectrum is found to carry second-order spectral signatures (e.g., small bands), which are connected with the underlying chemical diversity of populations. However, the precise attribution of theses signatures remains limited by the combined small size and heterogeneity of the sample of astronomical spectra available in this study. CONCLUSIONS The upcoming JWST data will allow us to overcome this limitation. The large data sets of hyperspectral images provided by JWST analysed with the proposed method, which is fast and robust, will open promising perspectives for our understanding of the chemical evolution of the AIB carriers.
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Affiliation(s)
- S Foschino
- Institut de Recherche en Astrophysique et Planetologie, Université de Toulouse, CNRS, CNES, UPS, Toulouse, France, 9 Av. du colonel Roche, 31028 Toulouse Cedex 04, France
| | - O Berné
- Institut de Recherche en Astrophysique et Planetologie, Université de Toulouse, CNRS, CNES, UPS, Toulouse, France, 9 Av. du colonel Roche, 31028 Toulouse Cedex 04, France
| | - C Joblin
- Institut de Recherche en Astrophysique et Planetologie, Université de Toulouse, CNRS, CNES, UPS, Toulouse, France, 9 Av. du colonel Roche, 31028 Toulouse Cedex 04, France
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20
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Abstract
This work presents a study of the thermal evaporation and stability of pyrene (C16H10)n clusters. Thermal evaporation rates of positively charged mass-selected clusters are measured for sizes in the range n = 3-40 pyrene units. The experimental setup consists of a gas aggregation source, a thermalization chamber, and a time of flight mass spectrometer. A microcanonical Phase Space Theory (PST) simulation is used to determine the dissociation energies of pyrene clusters by fitting the experimental breakdown curves. Calculations using the Density Functional based Tight Binding combined with a Configuration Interaction (CI-DFTB) model and a hierarchical optimization scheme are also performed in the range n = 2-7 to determine the harmonic frequencies and a theoretical estimation of the dissociation energies. The frequencies are used in the calculations of the density of states needed in the PST simulations, assuming an extrapolation scheme for clusters larger than 7 units. Using the PST model with a minimal set of adjustable parameters, we obtain good fits of the experimental breakdown curves over the full studied size range. The approximations inherent to the PST simulation and the influence of the used parameters are carefully estimated. The derived dissociation energies show significant variations over the studied size range. Compared with neutral clusters, significantly higher values of the dissociation energies are obtained for the smaller sizes and attributed to charge resonance in line with CI-DFTB calculations.
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Affiliation(s)
- Sébastien Zamitha
- Laboratoire Collisions Agrégats Réactivité (LCAR/IRSAMC) UMR5589, Université de Toulouse and CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
| | - Ming-Chao Ji
- Institut de Recherche en Astrophysique et Planétologie (IRAP) UMR5277, Université de Toulouse, CNRS, CNES, 9 avenue du Colonel Roche, F-31028 Toulouse, France
| | - Jean-Marc L’Hermite
- Laboratoire Collisions Agrégats Réactivité (LCAR/IRSAMC) UMR5589, Université de Toulouse and CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
| | - Christine Joblin
- Institut de Recherche en Astrophysique et Planétologie (IRAP) UMR5277, Université de Toulouse, CNRS, CNES, 9 avenue du Colonel Roche, F-31028 Toulouse, France
| | - Léo Dontot
- Institut de Recherche en Astrophysique et Planétologie (IRAP) UMR5277, Université de Toulouse, CNRS, CNES, 9 avenue du Colonel Roche, F-31028 Toulouse, France
- Laboratoire de Chimie et Physique Quantiques (LCPQ/IRSAMC) UMR5626, Université de Toulouse and CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
| | - Mathias Rapacioli
- Laboratoire de Chimie et Physique Quantiques (LCPQ/IRSAMC) UMR5626, Université de Toulouse and CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
| | - Fernand Spiegelman
- Laboratoire de Chimie et Physique Quantiques (LCPQ/IRSAMC) UMR5626, Université de Toulouse and CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
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21
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Garofano V, Bérard R, Boivin S, Joblin C, Makasheva K, Stafford L. Multi-scale investigation in the frequency domain of Ar/HMDSO dusty plasma with pulsed injection of HMDSO. Plasma Sources Sci Technol 2019; 28:055019. [PMID: 31327895 PMCID: PMC6640068 DOI: 10.1088/1361-6595/ab07cc] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
A combination of time-resolved optical emission spectroscopy measurements and collisional-radiative modeling is used to investigate the phenomena occurring over multiple time scales in the frequency domain of a low-pressure, axially-asymmetric capacitively-coupled RF argon plasma with pulsed injection of hexamethyldisiloxane (HMDSO, Si2O(CH3)6). The collisional-radiative model developed here considers the population of argon 1s and all ten 2p levels (in Paschen's notation). The presence of HMDSO in the plasma is accounted for in the model by quenching of the argon 1s states by species generated by plasma processing of HMDSO, including HMDSO-15 (Si2O(CH3)5), acetylene (C2H2) and methane (CH4). Detailed analysis of the relative populations of Ar 2p states reveals cyclic evolutions of the electron temperature, electron density and quenching frequency that are shown to be linked to the kinetics of dust formation in Ar/HMDSO plasmas. Penning ionization of HMDSO and its fragments is found to be an important source of electrons for the plasma maintenance. It is at the origin of the cyclic formation/disappearance of the dust cloud, without attenuation of the phenomenon, as long as the pulsed injection of HMDSO is sustained. The multi-scale approach used in this study further reveals the straightforward relation of the frequency of HMDSO pulsed injection, in particular the HMDSO duty cycle, with the frequency of dust formation/disappearance cycle.
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Affiliation(s)
- V. Garofano
- Département de physique, Université de Montréal, Montréal, Québec, Canada
| | - R. Bérard
- LAPLACE (Laboratoire Plasma et Conversion d’Energie), Université de Toulouse, CNRS, UPS, INPT, Toulouse, France
- IRAP (Institut de Recherche en Astrophysique et Planétologie), Université de Toulouse, CNRS, UPS, CNES, Toulouse, France
| | - S. Boivin
- Département de physique, Université de Montréal, Montréal, Québec, Canada
| | - C. Joblin
- IRAP (Institut de Recherche en Astrophysique et Planétologie), Université de Toulouse, CNRS, UPS, CNES, Toulouse, France
| | - K. Makasheva
- LAPLACE (Laboratoire Plasma et Conversion d’Energie), Université de Toulouse, CNRS, UPS, INPT, Toulouse, France
| | - L. Stafford
- Département de physique, Université de Montréal, Montréal, Québec, Canada
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22
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Chakraborty S, Mulas G, Demyk K, Joblin C. Experimental Approach to the Study of Anharmonicity in the Infrared Spectrum of Pyrene from 14 to 723 K. J Phys Chem A 2019; 123:4139-4148. [PMID: 31002512 PMCID: PMC6557715 DOI: 10.1021/acs.jpca.8b11016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Quantifying the effect of anharmonicity on the infrared spectrum of large molecules such as polycyclic aromatic hydrocarbons (PAHs) at high temperatures is the focus of a number of theoretical and experimental studies, many of them motivated by astrophysical applications. We recorded the IR spectrum of pyrene C16H10 microcrystals embedded in KBr pellets over a wide range of temperatures (14-723 K) and studied the evolution of band positions, widths, and integrated intensities with temperature. We identified jumps for some of the spectral characteristics of some bands in the 423-473 K range. These were attributed to a change of phase from crystal to molten in condensed pyrene, which appears to affect more strongly bands involving large CH motions. Empirical anharmonicity factors that quantify the linear evolution of band positions and widths with temperature for values larger than ∼150-250 K, depending on the band, were retrieved from both phases and averaged to provide recommended values for these anharmonicity factors. The derived values were found to be consistent with available gas phase data. We conclude about the relevance of the methodology to produce data that can be compared with calculated anharmonic IR spectra and provide input for models that simulate the IR emission of astro-PAHs.
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Affiliation(s)
- Shubhadip Chakraborty
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, CNRS, CNES, 9 Av. du Colonel Roche, 31028 Toulouse Cedex 4, France
| | - Giacomo Mulas
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, CNRS, CNES, 9 Av. du Colonel Roche, 31028 Toulouse Cedex 4, France
- Istituto Nazionale di Astrofisica (INAF), Osservatorio Astronomico di Cagliari, 09047 Selargius (CA), Italy
| | - Karine Demyk
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, CNRS, CNES, 9 Av. du Colonel Roche, 31028 Toulouse Cedex 4, France
| | - Christine Joblin
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, CNRS, CNES, 9 Av. du Colonel Roche, 31028 Toulouse Cedex 4, France
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23
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Jusko P, Simon A, Banhatti S, Brünken S, Joblin C. Cover Feature: Direct Evidence of the Benzylium and Tropylium Cations as the Two Long-Lived Isomers of C7
H7
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(ChemPhysChem 23/2018). Chemphyschem 2018. [DOI: 10.1002/cphc.201801055] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Pavol Jusko
- Institut de Recherche en Astrophysique et Planétologie (IRAP); Université de Toulouse (UPS), CNRS, CNES; 9 Av. du Colonel Roche 31028 Toulouse Cedex 4 France
| | - Aude Simon
- Laboratoire de Chimie et Physique Quantiques LCPQ/IRSAMC; Université de Toulouse (UPS) and CNRS; 118 Route de Narbonne 31062 Toulouse France
| | - Shreyak Banhatti
- I. Physikalisches Institut; Universität zu Köln; Zülpicher Str. 77 50937 Köln Germany
| | - Sandra Brünken
- Radboud University; Institute for Molecules and Materials, FELIX Laboratory; Toernooiveld 7c 6525 ED Nijmegen The Netherlands
| | - Christine Joblin
- Institut de Recherche en Astrophysique et Planétologie (IRAP); Université de Toulouse (UPS), CNRS, CNES; 9 Av. du Colonel Roche 31028 Toulouse Cedex 4 France
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24
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Mulas G, Falvo C, Cassam-Chenaï P, Joblin C. Publisher's Note: "Anharmonic vibrational spectroscopy of polycyclic aromatic hydrocarbons (PAHs)" [J. Chem. Phys. 149, 144102 (2018)]. J Chem Phys 2018; 149:189901. [PMID: 30441925 DOI: 10.1063/1.5080082] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Giacomo Mulas
- IRAP, Université de Toulouse, CNRS, UPS, CNES, 9 Av. Colonel Roche, 31028 Toulouse Cedex 4, France
| | - Cyril Falvo
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, University of Paris-Sud, Université Paris-Saclay, 91405 Orsay, France
| | | | - Christine Joblin
- IRAP, Université de Toulouse, CNRS, UPS, CNES, 9 Av. Colonel Roche, 31028 Toulouse Cedex 4, France
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25
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Abstract
While powerful techniques exist to accurately account for anharmonicity in vibrational molecular spectroscopy, they are computationally very expensive and cannot be routinely employed for large species and/or at non-zero vibrational temperatures. Motivated by the study of Polycyclic Aromatic Hydrocarbon (PAH) emission in space, we developed a new code, which takes into account all modes and can describe all infrared transitions including bands becoming active due to resonances as well as overtone, combination, and difference bands. In this article, we describe the methodology that was implemented and discuss how the main difficulties were overcome, so as to keep the problem tractable. Benchmarking with high-level calculations was performed on a small molecule. We carried out specific convergence tests on two prototypical PAHs, pyrene (C16H10) and coronene (C24H12), aiming at optimising tunable parameters to achieve both acceptable accuracy and computational costs for this class of molecules. We then report the results obtained at 0 K for pyrene and coronene, comparing the calculated spectra with available experimental data. The theoretical band positions were found to be significantly improved compared to harmonic density functional theory calculations. The band intensities are in reasonable agreement with experiments, the main limitation being the accuracy of the underlying calculations of the quartic force field. This is a first step toward calculating moderately high-temperature spectra of PAHs and other similarly rigid molecules using Monte Carlo sampling.
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Affiliation(s)
- Giacomo Mulas
- IRAP, Université de Toulouse, CNRS, UPS, CNES, 9 Av. du Colonel Roche, 31028 Toulouse Cedex 4, France
| | - Cyril Falvo
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, University of Paris-Sud, Université Paris-Saclay, 91405 Orsay, France
| | | | - Christine Joblin
- IRAP, Université de Toulouse, CNRS, UPS, CNES, 9 Av. du Colonel Roche, 31028 Toulouse Cedex 4, France
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Jusko P, Simon A, Banhatti S, Brünken S, Joblin C. Direct Evidence of the Benzylium and Tropylium Cations as the Two Long-Lived Isomers of C 7 H 7. Chemphyschem 2018; 19:3182-3185. [PMID: 30238585 PMCID: PMC6420061 DOI: 10.1002/cphc.201800744] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Indexed: 11/12/2022]
Abstract
Disentangling the isomeric structure of C7 H7 + is a longstanding experimental issue. We report here the full mid-infrared vibrational spectrum of C7 H7 + tagged with Ne obtained with infrared-predissociation spectroscopy at 10 K. Saturation depletion measurements were used to assign the contribution of benzylium and tropylium isomers and demonstrate that no other isomer is involved. Recorded spectral features compare well with density functional theory calculations. This opens perspectives for a better understanding and control of the formation paths leading to either tropylium or benzylium ions.
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Affiliation(s)
- Pavol Jusko
- Institut de Recherche en Astrophysique et Planétologie (IRAP), Université de Toulouse (UPS), CNRS, CNES, 9 Av. du Colonel Roche, 31028 Toulouse Cedex 4, France
| | - Aude Simon
- Laboratoire de Chimie et Physique Quantiques LCPQ/IRSAMC, Université de Toulouse (UPS) and CNRS, 118 Route de Narbonne, 31062 Toulouse, France
| | - Shreyak Banhatti
- I. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany
| | - Sandra Brünken
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7c, 6525 ED, Nijmegen, The Netherlands
| | - Christine Joblin
- Institut de Recherche en Astrophysique et Planétologie (IRAP), Université de Toulouse (UPS), CNRS, CNES, 9 Av. du Colonel Roche, 31028 Toulouse Cedex 4, France
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27
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Joblin C, Bron E, Pinto C, Pilleri P, Le Petit F, Gerin M, Le Bourlot J, Fuente A, Berne O, Goicoechea JR, Habart E, Köhler M, Teyssier D, Nagy Z, Montillaud J, Vastel C, Cernicharo J, Röllig M, Ossenkopf-Okada V, Bergin EA. Structure of photodissociation fronts in star-forming regions revealed by observations of high-J CO emission lines with Herschel. Astron Astrophys 2018; 615:A129. [PMID: 30185990 PMCID: PMC6120684 DOI: 10.1051/0004-6361/201832611] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
CONTEXT In bright photodissociation regions (PDRs) associated to massive star formation, the presence of dense "clumps" that are immersed in a less dense interclump medium is often proposed to explain the difficulty of models to account for the observed gas emission in high-excitation lines. AIMS We aim at presenting a comprehensive view of the modeling of the CO rotational ladder in PDRs, including the high-J lines that trace warm molecular gas at PDR interfaces. METHODS We observed the 12CO and 13CO ladders in two prototypical PDRs, the Orion Bar and NGC 7023 NW using the instruments onboard Herschel. We also considered line emission from key species in the gas cooling of PDRs (C+, O, H2) and other tracers of PDR edges such as OH and CH+. All the intensities are collected from Herschel observations, the literature and the Spitzer archive and are analyzed using the Meudon PDR code. RESULTS A grid of models was run to explore the parameter space of only two parameters: thermal gas pressure and a global scaling factor that corrects for approximations in the assumed geometry. We conclude that the emission in the high-J CO lines, which were observed up to J up =23 in the Orion Bar (J up =19 in NGC 7023), can only originate from small structures of typical thickness of a few 10-3 pc and at high thermal pressures (Pth ~ 108 K cm-3). CONCLUSIONS Compiling data from the literature, we found that the gas thermal pressure increases with the intensity of the UV radiation field given by G0, following a trend in line with recent simulations of the photoevaporation of illuminated edges of molecular clouds. This relation can help rationalising the analysis of high-J CO emission in massive star formation and provides an observational constraint for models that study stellar feedback on molecular clouds.
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Affiliation(s)
- C Joblin
- IRAP, Université de Toulouse, CNRS, UPS, CNES, 9 Av. colonel Roche, BP 44346, 31028 Toulouse Cedex 4, France
| | - E Bron
- Instituto de Fisica Fundamental (CSIC), Calle Serrano 121-123, 28006, Madrid, Spain
- LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, F-92190, Meudon, France
| | - C Pinto
- Aix-Marseille Université, CNRS, LAM (Laboratoire d'Astrophysique de Marseille) UMR 7326, 13388 Marseille, France
| | - P Pilleri
- IRAP, Université de Toulouse, CNRS, UPS, CNES, 9 Av. colonel Roche, BP 44346, 31028 Toulouse Cedex 4, France
| | - F Le Petit
- LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, F-92190, Meudon, France
| | - M Gerin
- LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, F-92190, Meudon, France
| | - J Le Bourlot
- LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, F-92190, Meudon, France
- Université Paris-Diderot, Paris, France
| | - A Fuente
- Observatorio Astronómico Nacional, Apdo. 112, 28803 Alcalá de Henares, Madrid, Spain
| | - O Berne
- IRAP, Université de Toulouse, CNRS, UPS, CNES, 9 Av. colonel Roche, BP 44346, 31028 Toulouse Cedex 4, France
| | - J R Goicoechea
- Instituto de Fisica Fundamental (CSIC), Calle Serrano 121-123, 28006, Madrid, Spain
| | - E Habart
- Institut d'Astrophysique Spatiale (IAS), Université Paris Sud & CNRS, 91405 Orsay, France
| | - M Köhler
- Institut d'Astrophysique Spatiale (IAS), Université Paris Sud & CNRS, 91405 Orsay, France
| | - D Teyssier
- European Space Astronomy Centre, ESA, PO Box 78, 28691 Villanueva de la Cañada, Madrid, Spain
| | - Z Nagy
- I. Physikalisches Institut der Universität zu Köln, Zülpicher Strasse 77, 50937 Köln, Germany
| | - J Montillaud
- Institut Utinam, CNRS UMR 6213, OSU THETA, Université de Franche-Comté, 41bis avenue de l'Observatoire, 25000 Besançon, France
| | - C Vastel
- IRAP, Université de Toulouse, CNRS, UPS, CNES, 9 Av. colonel Roche, BP 44346, 31028 Toulouse Cedex 4, France
| | - J Cernicharo
- Instituto de Fisica Fundamental (CSIC), Calle Serrano 121-123, 28006, Madrid, Spain
| | - M Röllig
- I. Physikalisches Institut der Universität zu Köln, Zülpicher Strasse 77, 50937 Köln, Germany
| | - V Ossenkopf-Okada
- I. Physikalisches Institut der Universität zu Köln, Zülpicher Strasse 77, 50937 Köln, Germany
| | - E A Bergin
- Department of Astronomy, University of Michigan, 311 West Hall, 1085 S. University Avenue, Ann Arbor, MI 48109, USA
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Castillo SR, Simon A, Joblin C. Investigating the importance of edge-structure in the loss of H/H 2 of PAH cations: the case of dibenzopyrene isomers. Int J Mass Spectrom 2018; 429:189-197. [PMID: 30186034 PMCID: PMC6120680 DOI: 10.1016/j.ijms.2017.09.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We present a detailed study of the main dehydrogenation processes of two dibenzopyrene cation (C24H14+) isomers, namely dibenzo(a,e)pyrene (AE+) and dibenzo(a,l)pyrene (AL+). First, action spectroscopy under VUV photons was performed using synchrotron radiation in the 8-20 eV range. We observed lower dissociation thresholds for the non-planar molecule (AL+) than for the planar one (AE+) for the main dissociation pathways: H and 2H/H2 loss. In order to rationalize the experimental results, dissociation paths were investigated by means of density functional theory calculations. In the case of H loss, which is the dominant channel at the lowest energies, the observed difference between the two isomers can be explained by the presence in AL+ of two C-H bonds with considerably lower adiabatic dissociation energies. In both isomers the 2H/H2 loss channels are observed only at about 1 eV higher than H loss. We suggest that this is due to the propensity of bay H atoms to easily form H2. In addition, in the case of AL+, we cannot exclude a competition between 2H and H2 channels. In particular, the formation of a stable dissociation product with a five-membered ring could account for the low energy sequential loss of 2 hydrogens. This work shows the potential role of non-compact PAHs containing bay regions in the production of H2 in space.
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Affiliation(s)
- Sarah Rodriguez Castillo
- Institut de Recherche en Astrophysique et Planétologie IRAP, Université de Toulouse (UPS), CNRS, CNES, 9 Av. du Colonel Roche, 31028 Toulouse Cedex 4, France
- Laboratoire de Chimie et Physique Quantiques LCPQ/IRSAMC, Université de Toulouse (UPS) and CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
| | - Aude Simon
- Laboratoire de Chimie et Physique Quantiques LCPQ/IRSAMC, Université de Toulouse (UPS) and CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
| | - Christine Joblin
- Institut de Recherche en Astrophysique et Planétologie IRAP, Université de Toulouse (UPS), CNRS, CNES, 9 Av. du Colonel Roche, 31028 Toulouse Cedex 4, France
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Abstract
The fragment of the 1-methylpyrene cation, C 17 H 11 + , is expected to exist in two isomeric forms, 1-pyrenemethylium PyrCH 2 + and the tropylium containing species PyrC 7 + . We measured the infrared (IR) action spectrum of cold C 17 H 11 + tagged with Ne using a cryogenic ion trap instrument coupled to the FELIX laser. Comparison of the experimental data with density functional theory calculations allows us to identify the PyrCH 2 + isomer in our experiments. The IR Multi-Photon Dissociation spectrum was also recorded following the C2H2 loss channel. Its analysis suggests combined effects of anharmonicity and isomerisation while heating the trapped ions, as shown by molecular dynamics simulations.
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Affiliation(s)
- Pavol Jusko
- Institut de Recherche en Astrophysique et Planétologie (IRAP), Université de Toulouse (UPS), CNRS, CNES, 9 Av. du Colonel Roche, 31028 Toulouse Cedex 4, France
- I. Physikalisches Institut, Universität zu Käoln, Zülpicher Str. 77, 50937 Köln, Germany
| | - Aude Simon
- Laboratoire de Chimie et Physique Quantiques LCPQ/IRSAMC, Université de Toulouse (UPS) and CNRS, 118 Route de Narbonne, 31062 Toulouse, France
| | - Gabi Wenzel
- Institut de Recherche en Astrophysique et Planétologie (IRAP), Université de Toulouse (UPS), CNRS, CNES, 9 Av. du Colonel Roche, 31028 Toulouse Cedex 4, France
| | - Sandra Brünken
- I. Physikalisches Institut, Universität zu Käoln, Zülpicher Str. 77, 50937 Köln, Germany
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7c, 6525 ED Nijmegen, The Netherlands
| | - Stephan Schlemmer
- I. Physikalisches Institut, Universität zu Käoln, Zülpicher Str. 77, 50937 Köln, Germany
| | - Christine Joblin
- Institut de Recherche en Astrophysique et Planétologie (IRAP), Université de Toulouse (UPS), CNRS, CNES, 9 Av. du Colonel Roche, 31028 Toulouse Cedex 4, France
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30
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West B, Rodriguez Castillo S, Sit A, Mohamad S, Lowe B, Joblin C, Bodi A, Mayer PM. Unimolecular reaction energies for polycyclic aromatic hydrocarbon ions. Phys Chem Chem Phys 2018; 20:7195-7205. [PMID: 29480289 PMCID: PMC6031295 DOI: 10.1039/c7cp07369k] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Imaging photoelectron photoion coincidence spectroscopy was employed to explore the unimolecular dissociation of the ionized polycyclic aromatic hydrocarbons (PAHs) acenaphthylene, fluorene, cyclopenta[d,e,f]phenanthrene, pyrene, perylene, fluoranthene, dibenzo[a,e]pyrene, dibenzo[a,l]pyrene, coronene and corannulene. The primary reaction is always hydrogen atom loss, with the smaller species also exhibiting loss of C2H2 to varying extents. Combined with previous work on smaller PAH ions, trends in the reaction energies (E0) for loss of H from sp2-C and sp3-C centres, along with hydrocarbon molecule loss were found as a function of the number of carbon atoms in the ionized PAHs ranging in size from naphthalene to coronene. In the case of molecules which possessed at least one sp3-C centre, the activation energy for the loss of an H atom from this site was 2.34 eV, with the exception of cyclopenta[d,e,f]phenanthrene (CPP) ions, for which the E0 was 3.44 ± 0.86 eV due to steric constraints. The hydrogen loss from PAH cations and from their H-loss fragments exhibits two trends, depending on the number of unpaired electrons. For the loss of the first hydrogen atom, the energy is consistently ca. 4.40 eV, while the threshold to lose the second hydrogen atom is much lower at ca. 3.16 eV. The only exception was for the dibenzo[a,l]pyrene cation, which has a unique structure due to steric constraints, resulting in a low H loss reaction energy of 2.85 eV. If C2H2 is lost directly from the precursor cation, the energy required for this dissociation is 4.16 eV. No other fragmentation channels were observed over a large enough sample set for trends to be extrapolated, though data on CH3 and C4H2 loss obtained in previous studies is included for completeness. The dissociation reactions were also studied by collision induced dissociation after ionization by atmospheric pressure chemical ionization. When modeled with a simple temperature-based theory for the post-collision internal energy distribution, there was reasonable agreement between the two sets of data.
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Affiliation(s)
- Brandi West
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa K1N 6N5, Canada.
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31
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Affiliation(s)
- Christine Joblin
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse (UPS), CNRS, 31028 Toulouse Cedex 4, France.
| | - José Cernicharo
- Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Científicas (CSIC), Molecular Astrophysics Group, Cantoblanco, 28049 Madrid, Spain
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32
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Tanarro I, Alemán B, de Vicente P, Gallego JD, Pardo JR, Santoro G, Lauwaet K, Tercero F, Díaz-Pulido A, Moreno E, Agúndez M, Goicoechea JR, Sobrado JM, López JA, Martínez L, Doménech JL, Herrero VJ, Hernández JM, Peláez RJ, López-Pérez JA, Gómez-González J, Alonso JL, Jiménez E, Teyssier D, Makasheva K, Castellanos M, Joblin C, Martín-Gago JA, Cernicharo J. Using radio astronomical receivers for molecular spectroscopic characterization in astrochemical laboratory simulations: A proof of concept. Astron Astrophys 2018; 609:A15. [PMID: 29277841 PMCID: PMC5741178 DOI: 10.1051/0004-6361/201730969] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We present a proof of concept on the coupling of radio astronomical receivers and spectrometers with chemical reactors and the performances of the resulting setup for spectroscopy and chemical simulations in laboratory astrophysics. Several experiments including cold plasma generation and UV photochemistry were performed in a 40 cm long gas cell placed in the beam path of the Aries 40 m radio telescope receivers operating in the 41-49 GHz frequency range interfaced with fast Fourier transform spectrometers providing 2 GHz bandwidth and 38 kHz resolution. The impedance matching of the cell windows has been studied using different materials. The choice of the material and its thickness was critical to obtain a sensitivity identical to that of standard radio astronomical observations. Spectroscopic signals arising from very low partial pressures of CH3OH, CH3CH2OH, HCOOH, OCS, CS, SO2 (<10-3 mbar) were detected in a few seconds. Fast data acquisition was achieved allowing for kinetic measurements in fragmentation experiments using electron impact or UV irradiation. Time evolution of chemical reactions involving OCS, O2 and CS2 was also observed demonstrating that reactive species, such as CS, can be maintained with high abundance in the gas phase during these experiments.
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Affiliation(s)
- I Tanarro
- IEM. CSIC. Instituto de Estructura de la Materia. Molecular Physics Department. C/Serrano 123, 28006 Madrid, Spain
| | - B Alemán
- ICMM. CSIC. Molecular Astrophysics Group. C/ Sor Juana Inés de la Cruz 3. Cantoblanco, 28049 Madrid. Spain
| | - P de Vicente
- Centro Nacional de Tecnologías Radioastronómicas y Aplicaciones Geoespaciales (CNTRAG), Observatorio de Yebes (IGN), Spain
| | - J D Gallego
- Centro Nacional de Tecnologías Radioastronómicas y Aplicaciones Geoespaciales (CNTRAG), Observatorio de Yebes (IGN), Spain
| | - J R Pardo
- ICMM. CSIC. Molecular Astrophysics Group. C/ Sor Juana Inés de la Cruz 3. Cantoblanco, 28049 Madrid. Spain
| | - G Santoro
- ICMM. CSIC. Materials Science Factory. Structure of Nanoscopic Systems Group, ESISNA. C/ Sor Juana Inés de la Cruz 3. Cantoblanco, 28049 Madrid. Spain
| | - K Lauwaet
- ICMM. CSIC. Materials Science Factory. Structure of Nanoscopic Systems Group, ESISNA. C/ Sor Juana Inés de la Cruz 3. Cantoblanco, 28049 Madrid. Spain
| | - F Tercero
- Centro Nacional de Tecnologías Radioastronómicas y Aplicaciones Geoespaciales (CNTRAG), Observatorio de Yebes (IGN), Spain
| | - A Díaz-Pulido
- Centro Nacional de Tecnologías Radioastronómicas y Aplicaciones Geoespaciales (CNTRAG), Observatorio de Yebes (IGN), Spain
| | - E Moreno
- ICMM. CSIC. Molecular Astrophysics Group. C/ Sor Juana Inés de la Cruz 3. Cantoblanco, 28049 Madrid. Spain
| | - M Agúndez
- ICMM. CSIC. Molecular Astrophysics Group. C/ Sor Juana Inés de la Cruz 3. Cantoblanco, 28049 Madrid. Spain
| | - J R Goicoechea
- ICMM. CSIC. Molecular Astrophysics Group. C/ Sor Juana Inés de la Cruz 3. Cantoblanco, 28049 Madrid. Spain
| | - J M Sobrado
- Centro de Astrobiología, (CAB-CSIC/INTA). Carretera Torrejón a Ajalvir km 4, Torrejón de Ardoz 28850 (Madrid), Spain
| | - J A López
- Centro Nacional de Tecnologías Radioastronómicas y Aplicaciones Geoespaciales (CNTRAG), Observatorio de Yebes (IGN), Spain
| | - L Martínez
- ICMM. CSIC. Materials Science Factory. Structure of Nanoscopic Systems Group, ESISNA. C/ Sor Juana Inés de la Cruz 3. Cantoblanco, 28049 Madrid. Spain
| | - J L Doménech
- IEM. CSIC. Instituto de Estructura de la Materia. Molecular Physics Department. C/Serrano 123, 28006 Madrid, Spain
| | - V J Herrero
- IEM. CSIC. Instituto de Estructura de la Materia. Molecular Physics Department. C/Serrano 123, 28006 Madrid, Spain
| | - J M Hernández
- Centro Nacional de Tecnologías Radioastronómicas y Aplicaciones Geoespaciales (CNTRAG), Observatorio de Yebes (IGN), Spain
| | - R J Peláez
- IEM. CSIC. Instituto de Estructura de la Materia. Molecular Physics Department. C/Serrano 123, 28006 Madrid, Spain
| | - J A López-Pérez
- Centro Nacional de Tecnologías Radioastronómicas y Aplicaciones Geoespaciales (CNTRAG), Observatorio de Yebes (IGN), Spain
| | - J Gómez-González
- Centro Nacional de Tecnologías Radioastronómicas y Aplicaciones Geoespaciales (CNTRAG), Observatorio de Yebes (IGN), Spain
| | - J L Alonso
- Grupo de Espectroscopía Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopía y Bioespectroscopía, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, 47011 Valladolid, Spain
| | - E Jiménez
- Departamento de Química Física, Facultad de Ciencias y Tecnologías Químicas, Universidad de Castilla-La Mancha, Avda. Camilo José Cela 1B, E-13071, Ciudad Real, Spain
| | - D Teyssier
- European Space Astronomy Centre, ESA, PO Box 78, 28691 Villanueva de la Cañada, Madrid, Spain
| | - K Makasheva
- LAPLACE (Laboratoire Plasma et Conversion dÉnergie); Université de Toulouse; CNRS, UPS, INPT; 118 route de Narbonne, F-31062 Toulouse cedex 9, France
| | - M Castellanos
- ICMM. CSIC. Molecular Astrophysics Group. C/ Sor Juana Inés de la Cruz 3. Cantoblanco, 28049 Madrid. Spain
| | - C Joblin
- Université de Toulouse, UPS-OMS, IRAP, 31000 Toulouse, France
- CNRS, IRAP, 9 Av. Colonel Roche, BP 44346, 31028 Toulouse Cedex 4, France
| | - J A Martín-Gago
- ICMM. CSIC. Materials Science Factory. Structure of Nanoscopic Systems Group, ESISNA. C/ Sor Juana Inés de la Cruz 3. Cantoblanco, 28049 Madrid. Spain
| | - J Cernicharo
- ICMM. CSIC. Molecular Astrophysics Group. C/ Sor Juana Inés de la Cruz 3. Cantoblanco, 28049 Madrid. Spain
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Cox NLJ, Cami J, Farhang A, Smoker J, Monreal-Ibero A, Lallement R, Sarre PJ, Marshall CCM, Smith KT, Evans CJ, Royer P, Linnartz H, Cordiner MA, Joblin C, van Loon JT, Foing BH, Bhatt NH, Bron E, Elyajouri M, de Koter A, Ehrenfreund P, Javadi A, Kaper L, Khosroshadi HG, Laverick M, Le Petit F, Mulas G, Roueff E, Salama F, Spaans M. The ESO Diffuse Interstellar Bands Large Exploration Survey: EDIBLES I. Project description, survey sample and quality assessment. Astron Astrophys 2017; 606:A76. [PMID: 29151608 PMCID: PMC5693340 DOI: 10.1051/0004-6361/201730912] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The carriers of the diffuse interstellar bands (DIBs) are largely unidentified molecules ubiquitously present in the interstellar medium (ISM). After decades of study, two strong and possibly three weak near-infrared DIBs have recently been attributed to the [Formula: see text] fullerene based on observational and laboratory measurements. There is great promise for the identification of the over 400 other known DIBs, as this result could provide chemical hints towards other possible carriers. In an effort to systematically study the properties of the DIB carriers, we have initiated a new large-scale observational survey: the ESO Diffuse Interstellar Bands Large Exploration Survey (EDIBLES). The main objective is to build on and extend existing DIB surveys to make a major step forward in characterising the physical and chemical conditions for a statistically significant sample of interstellar lines-of-sight, with the goal to reverse-engineer key molecular properties of the DIB carriers. EDIBLES is a filler Large Programme using the Ultraviolet and Visual Echelle Spectrograph at the Very Large Telescope at Paranal, Chile. It is designed to provide an observationally unbiased view of the presence and behaviour of the DIBs towards early-spectral type stars whose lines-of-sight probe the diffuse-to-translucent ISM. Such a complete dataset will provide a deep census of the atomic and molecular content, physical conditions, chemical abundances and elemental depletion levels for each sightline. Achieving these goals requires a homogeneous set of high-quality data in terms of resolution (R ~ 70 000 - 100 000), sensitivity (S/N up to 1000 per resolution element), and spectral coverage (305-1042 nm), as well as a large sample size (100+ sightlines). In this first paper the goals, objectives and methodology of the EDIBLES programme are described and an initial assessment of the data is provided.
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Affiliation(s)
- Nick L J Cox
- Université de Toulouse, UPS-OMP, IRAP, 31028, Toulouse, France
- CNRS, IRAP, 9 Av. colonel Roche, BP 44346, F-31028 Toulouse, France
| | - Jan Cami
- Department of Physics and Astronomy, The University of Western Ontario, London, ON N6A 3K7, Canada
- SETI Institute, 189 Bernardo Avenue, Suite 100, Mountain View, CA 94043, USA
| | - Amin Farhang
- School of Astronomy, Institute for Research in Fundamental Sciences, 19395-5531 Tehran, Iran
| | - Jonathan Smoker
- European Southern Observatory, Alonso de Cordova 3107, Vitacura, Santiago, Chile
| | - Ana Monreal-Ibero
- GEPI, Observatoire de Paris, PSL Research University, CNRS, Université Paris-Diderot, Sorbonne Paris Cité, Place Jules Janssen, 92195 Meudon, France
- Instituto de Astrofísica de Canarias (IAC), E-38205 La Laguna, Tenerife, Spain
- Universidad de La Laguna, Dpto. Astrofísica, E-38206 La Laguna, Tenerife, Spain
| | - Rosine Lallement
- GEPI, Observatoire de Paris, PSL Research University, CNRS, Université Paris-Diderot, Sorbonne Paris Cité, Place Jules Janssen, 92195 Meudon, France
| | - Peter J Sarre
- School of Chemistry, The University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Charlotte C M Marshall
- School of Chemistry, The University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Keith T Smith
- Royal Astronomical Society, Burlington House, Piccadilly, London W1J 0BQ, UK
- AAAS Science International, Clarendon House, Clarendon Road, Cambridge CB2 8FH, UK
| | - Christopher J Evans
- UK Astronomy Technology Centre, Royal Observatory, Blackford Hill, Edinburgh, EH9 3HJ, UK
| | - Pierre Royer
- Instituut voor Sterrenkunde, KULeuven, Celestijnenlaan 200D, bus 2401, Leuven, Belgium
| | - Harold Linnartz
- Sackler Laboratory for Astrophysics, Leiden Observatory, Leiden University, PO Box 9513, NL2300 RA Leiden, The Netherlands
| | - Martin A Cordiner
- Astrochemistry Laboratory, NASA Goddard Space Flight Center, Code 691, 8800 Greenbelt Road, Greenbelt, MD 20771, USA
- Department of Physics, The Catholic University of America, Washington, DC 20064, USA
| | - Christine Joblin
- Université de Toulouse, UPS-OMP, IRAP, 31028, Toulouse, France
- CNRS, IRAP, 9 Av. colonel Roche, BP 44346, F-31028 Toulouse, France
| | | | | | - Neil H Bhatt
- Department of Physics and Astronomy, The University of Western Ontario, London, ON N6A 3K7, Canada
| | | | - Meriem Elyajouri
- GEPI, Observatoire de Paris, PSL Research University, CNRS, Université Paris-Diderot, Sorbonne Paris Cité, Place Jules Janssen, 92195 Meudon, France
| | - Alex de Koter
- Anton Pannekoek Institute for Astronomy, University of Amsterdam, NL-1090 GE Amsterdam, The Netherlands
- Instituut voor Sterrenkunde, KULeuven, Celestijnenlaan 200D, bus 2401, Leuven, Belgium
| | | | - Atefeh Javadi
- School of Astronomy, Institute for Research in Fundamental Sciences, 19395-5531 Tehran, Iran
| | - Lex Kaper
- Anton Pannekoek Institute for Astronomy, University of Amsterdam, NL-1090 GE Amsterdam, The Netherlands
| | - Habib G Khosroshadi
- School of Astronomy, Institute for Research in Fundamental Sciences, 19395-5531 Tehran, Iran
| | - Mike Laverick
- Instituut voor Sterrenkunde, KULeuven, Celestijnenlaan 200D, bus 2401, Leuven, Belgium
| | - Franck Le Petit
- LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Université Paris 06, 92190 Meudon, France
| | - Giacomo Mulas
- INAF - Osservatorio Astronomico di Cagliari, Via della Scienza 5, I-09047 Selargius, Italy
| | - Evelyne Roueff
- LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Université Paris 06, 92190 Meudon, France
| | - Farid Salama
- NASA Ames Research Center, Space Science & Astrobiology Division, Moffett Field, California, USA
| | - Marco Spaans
- Kapteyn Institute, University of Groningen, Groningen, The Netherlands
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Abstract
Emission of fullerenes in their infrared vibrational bands has been detected in space near hot stars. The proposed attribution of the diffuse interstellar bands at 9577 and 9632 Å to electronic transitions of the buckminsterfullerene cation (i.e. [Formula: see text]) was recently supported by new laboratory data, confirming the presence of this species in the diffuse interstellar medium (ISM). In this letter, we present the detection, also in the diffuse ISM, of the 17.4 and 18.9 μm emission bands commonly attributed to vibrational bands of neutral C60. According to classical models that compute the charge state of large molecules in space, C60 is expected to be mostly neutral in the diffuse ISM. This is in agreement with the abundances of diffuse C60 we derive here from observations. We also find that C60 is less abundant in the diffuse ISM than in star-forming regions, supporting the theory that C60 can be formed in these regions.
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Affiliation(s)
- O Berné
- Université de Toulouse; UPS-OMP; IRAP; Toulouse, France
- CNRS; IRAP; 9 Av. colonel Roche, BP 44346, F-31028 Toulouse cedex 4, France
| | - N L J Cox
- Université de Toulouse; UPS-OMP; IRAP; Toulouse, France
- CNRS; IRAP; 9 Av. colonel Roche, BP 44346, F-31028 Toulouse cedex 4, France
| | - G Mulas
- Istituto Nazionale di Astrofisica - Osservatorio Astronomico di Cagliari - strada 54, localit Poggio dei Pini, 09012- Capoterra (CA), Italy
| | - C Joblin
- Université de Toulouse; UPS-OMP; IRAP; Toulouse, France
- CNRS; IRAP; 9 Av. colonel Roche, BP 44346, F-31028 Toulouse cedex 4, France
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Joblin C, Dontot L, Garcia GA, Spiegelman F, Rapacioli M, Nahon L, Parneix P, Pino T, Bréchignac P. Size Effect in the Ionization Energy of PAH Clusters. J Phys Chem Lett 2017; 8:3697-3702. [PMID: 28742357 PMCID: PMC5545758 DOI: 10.1021/acs.jpclett.7b01546] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2017] [Accepted: 07/25/2017] [Indexed: 05/12/2023]
Abstract
We report the first experimental measurement of the near-threshold photoionization spectra of polycyclic aromatic hydrocarbon clusters made of pyrene C16H10 and coronene C24H12, obtained using imaging photoelectron-photoion coincidence spectrometry with a VUV synchrotron beamline. The experimental results of the ionization energy are compared to calculated ones obtained from simulations using dedicated electronic structure treatment for large ionized molecular clusters. Experiment and theory consistently find a decrease of the ionization energy with cluster size. The inclusion of temperature effects in the simulations leads to a lowering of this energy and to quantitative agreement with the experiment. In the case of pyrene, both theory and experiment show a discontinuity in the IE trend for the hexamer. This work demonstrates the ability of the models to describe the electronic structure of PAH clusters and suggests that these species are ionized in astronomical environments where they are thought to be present.
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Affiliation(s)
- C. Joblin
- IRAP, Université de
Toulouse, CNRS, UPS, CNES, 9 Av. du Colonel Roche, 31028 Toulouse Cedex 4, France
| | - L. Dontot
- IRAP, Université de
Toulouse, CNRS, UPS, CNES, 9 Av. du Colonel Roche, 31028 Toulouse Cedex 4, France
| | - G. A. Garcia
- Synchrotron
SOLEIL, L’Orme
des Merisiers, 91192 Gif sur Yvette Cedex, France
| | - F. Spiegelman
- Laboratoire
de Chimie et Physique Quantiques LCPQ/IRSAMC, Université de Toulouse (UPS) and CNRS, 118 Route de Narbonne, 31062 Toulouse, France
| | - M. Rapacioli
- Laboratoire
de Chimie et Physique Quantiques LCPQ/IRSAMC, Université de Toulouse (UPS) and CNRS, 118 Route de Narbonne, 31062 Toulouse, France
| | - L. Nahon
- Synchrotron
SOLEIL, L’Orme
des Merisiers, 91192 Gif sur Yvette Cedex, France
| | - P. Parneix
- Institut
des Sciences Moléculaires d’Orsay, CNRS, Univ Paris
Sud, Université Paris-Saclay, F-91405 Orsay, France
| | - T. Pino
- Institut
des Sciences Moléculaires d’Orsay, CNRS, Univ Paris
Sud, Université Paris-Saclay, F-91405 Orsay, France
| | - P. Bréchignac
- Institut
des Sciences Moléculaires d’Orsay, CNRS, Univ Paris
Sud, Université Paris-Saclay, F-91405 Orsay, France
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Champion J, Berné O, Vicente S, Kamp I, Le Petit F, Gusdorf A, Joblin C, Goicoechea JR. Herschel survey and modelling of externally-illuminated photoevaporating protoplanetary disks. Astron Astrophys 2017; 604:A69. [PMID: 29093599 PMCID: PMC5662148 DOI: 10.1051/0004-6361/201629404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
CONTEXT Protoplanetary disks undergo substantial mass-loss by photoevaporation, a mechanism which is crucial to their dynamical evolution. However, the processes regulating the gas energetics have not been well constrained by observations so far. AIMS We aim at studying the processes involved in disk photoevaporation when it is driven by far-UV photons (i.e. 6 < E < 13.6 eV). METHODS We present a unique Herschel survey and new ALMA observations of four externally-illuminated photoevaporating disks (a.k.a. proplyds). For the analysis of these data, we developed a 1D model of the photodissociation region (PDR) of a proplyd, based on the Meudon PDR code and we computed the far infrared line emission. RESULTS With this model, we successfully reproduce most of the observations and derive key physical parameters, i.e. densities at the disk surface of about 106 cm-3 and local gas temperatures of about 1000 K. Our modelling suggests that all studied disks are found in a transitional regime resulting from the interplay between several heating and cooling processes that we identify. These differ from those dominating in classical PDRs i.e. grain photo-electric effect and cooling by [OI] and [CII] FIR lines. This specific energetic regime is associated to an equilibrium dynamical point of the photoevaporation flow: the mass-loss rate is self-regulated to keep the envelope column density at a value that maintains the temperature at the disk surface around 1000 K. From the physical parameters derived from our best-fit models, we estimate mass-loss rates - of the order of 10-7 M⊙/yr - that are in agreement with earlier spectroscopic observation of ionised gas tracers. This holds only if we assume photoevaporation in the supercritical regime where the evaporation flow is launched from the disk surface at sound speed. CONCLUSIONS We have identified the energetic regime regulating FUV-photoevaporation in proplyds. This regime could be implemented into models of the dynamical evolution of protoplanetary disks.
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Affiliation(s)
- J Champion
- Université de Toulouse, UPS-OMP, IRAP, Toulouse, France
- CNRS, IRAP, 9 Av. colonel Roche, BP 44346, 31028 Toulouse Cedex 4, France
| | - O Berné
- Université de Toulouse, UPS-OMP, IRAP, Toulouse, France
- CNRS, IRAP, 9 Av. colonel Roche, BP 44346, 31028 Toulouse Cedex 4, France
| | - S Vicente
- Kapteyn Astronomical Institute, University of Groningen, Postbus 800, 9700 AV Groningen, The Netherlands
- Institute of Astrophysics and Space Sciences (IA), Tapada da Ajuda - Edificio Leste - 2° Piso, 1349-018 Lisboa, Portugal
| | - I Kamp
- Kapteyn Astronomical Institute, University of Groningen, Postbus 800, 9700 AV Groningen, The Netherlands
| | - F Le Petit
- LERMA, Observatoire de Paris, PSL Research University, CNRS, UMR8112, F-92190 Meudon, France
| | - A Gusdorf
- LERMA, Observatoire de Paris, École normale supérieure, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, F-75231, Paris, France
| | - C Joblin
- Université de Toulouse, UPS-OMP, IRAP, Toulouse, France
- CNRS, IRAP, 9 Av. colonel Roche, BP 44346, 31028 Toulouse Cedex 4, France
| | - J R Goicoechea
- Grupo de Astrofisica Molecular, Instituto de Ciencia de Materiales de Madrid (CSIC), E-28049, Madrid, Spain
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37
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Sabbah H, Bonnamy A, Papanastasiou D, Cernicharo J, Martín-Gago JA, Joblin C. Identification of PAH Isomeric Structure in Cosmic Dust Analogues: the AROMA setup. Astrophys J 2017; 843:34. [PMID: 28835724 PMCID: PMC5564497 DOI: 10.3847/1538-4357/aa73dd] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We developed a new analytical experimental setup called AROMA (Astrochemistry Research of Organics with Molecular Analyzer) that combines laser desorption/ionization techniques with ion trap mass spectrometry. We report here on the ability of the apparatus to detect aromatic species in complex materials of astrophysical interests and characterize their structures. A limit of detection of 100 femto-grams has been achieved using pure polycyclic aromatic hydrocarbon (PAH) samples, which corresponds to 2x108 molecules in the case of coronene (C24H12). We detected the PAH distribution in the Murchison meteorite, which is made of a complex mixture of extraterrestrial organic compounds. In addition, collision induced dissociation experiments were performed on selected species detected in Murchison, which led to the first firm identification of pyrene and its methylated derivatives in this sample.
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Affiliation(s)
- Hassan Sabbah
- Université de Toulouse, UPS-OMP, Institut de Recherche en Astrophysique et Planétologie, 9 avenue du Colonel Roche, 31028 Toulouse Cedex 4 (France)
- CNRS, IRAP, 9 avenue du Colonel Roche, 31028 Toulouse Cedex 4 (France)
- CNRS, LCAR, IRSAMC, 118 route de Narbonne, 31013 Toulouse Cedex 6, (France)
| | - Anthony Bonnamy
- Université de Toulouse, UPS-OMP, Institut de Recherche en Astrophysique et Planétologie, 9 avenue du Colonel Roche, 31028 Toulouse Cedex 4 (France)
- CNRS, IRAP, 9 avenue du Colonel Roche, 31028 Toulouse Cedex 4 (France)
| | | | - Jose Cernicharo
- Instituto de Ciencia de Materiales de Madrid, Sor Juana Inés de la Cruz, 3, Cantoblanco, 28049 Madrid, Spain
| | - Jose-Angel Martín-Gago
- Instituto de Ciencia de Materiales de Madrid, Sor Juana Inés de la Cruz, 3, Cantoblanco, 28049 Madrid, Spain
| | - Christine Joblin
- Université de Toulouse, UPS-OMP, Institut de Recherche en Astrophysique et Planétologie, 9 avenue du Colonel Roche, 31028 Toulouse Cedex 4 (France)
- CNRS, IRAP, 9 avenue du Colonel Roche, 31028 Toulouse Cedex 4 (France)
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38
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Agúndez M, Cernicharo J, Quintana-Lacaci G, Castro-Carrizo A, Velilla Prieto L, Marcelino N, Guélin M, Joblin C, Martín-Gago JA, Gottlieb CA, Patel NA, McCarthy MC. The growth of carbon chains in IRC +10216 mapped with ALMA. Astron Astrophys 2017; 601:A4. [PMID: 28469283 PMCID: PMC5405872 DOI: 10.1051/0004-6361/201630274] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Linear carbon chains are common in various types of astronomical molecular sources. Possible formation mechanisms involve both bottom-up and top-down routes. We have carried out a combined observational and modeling study of the formation of carbon chains in the C-star envelope IRC +10216, where the polymerization of acetylene and hydrogen cyanide induced by ultraviolet photons can drive the formation of linear carbon chains of increasing length. We have used ALMA to map the emission of λ 3 mm rotational lines of the hydrocarbon radicals C2H, C4H, and C6H, and the CN-containing species CN, C3N, HC3N, and HC5N with an angular resolution of ~1″. The spatial distribution of all these species is a hollow, 5-10″ wide, spherical shell located at a radius of 10-20″ from the star, with no appreciable emission close to the star. Our observations resolve the broad shell of carbon chains into thinner sub-shells which are 1-2″ wide and not fully concentric, indicating that the mass loss process has been discontinuous and not fully isotropic. The radial distributions of the species mapped reveal subtle differences: while the hydrocarbon radicals have very similar radial distributions, the CN-containing species show more diverse distributions, with HC3N appearing earlier in the expansion and the radical CN extending later than the rest of the species. The observed morphology can be rationalized by a chemical model in which the growth of polyynes is mainly produced by rapid gas-phase chemical reactions of C2H and C4H radicals with unsaturated hydrocarbons, while cyanopolyynes are mainly formed from polyynes in gas-phase reactions with CN and C3N radicals.
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Affiliation(s)
- M Agúndez
- Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Spain
| | - J Cernicharo
- Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Spain
| | - G Quintana-Lacaci
- Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Spain
| | - A Castro-Carrizo
- Institut de Radioastronomie Millimétrique, 300 rue de la Piscine, 38406 St. Martin d'Héres, France
| | - L Velilla Prieto
- Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Spain
| | - N Marcelino
- Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Spain
| | - M Guélin
- Institut de Radioastronomie Millimétrique, 300 rue de la Piscine, 38406 St. Martin d'Héres, France
| | - C Joblin
- Université de Toulouse, UPS-OMS, IRAP, 31000 Toulouse, France
- CNRS, IRAP, 9 Av. Colonel Roche, BP 44346, 31028 Toulouse Cedex 4, France
| | - J A Martín-Gago
- Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Spain
| | - C A Gottlieb
- Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
| | - N A Patel
- Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
| | - M C McCarthy
- Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
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Parikka A, Habart E, Bernard-Salas J, Goicoechea JR, Abergel A, Pilleri P, Dartois E, Joblin C, Gerin M, Godard B. Spatial distribution of FIR rotationally excited CH + and OH emission lines in the Orion Bar PDR. Astron Astrophys 2017; 599:A20. [PMID: 28260804 PMCID: PMC5334792 DOI: 10.1051/0004-6361/201629445] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
CONTEXT The methylidyne cation (CH+) and hydroxyl (OH) are key molecules in the warm interstellar chemistry, but their formation and excitation mechanisms are not well understood. Their abundance and excitation are predicted to be enhanced by the presence of vibrationally excited H2 or hot gas (~500-1000 K) in photodissociation regions with high incident FUV radiation field. The excitation may also originate in dense gas (> 105 cm-3) followed by nonreactive collisions with H2, H, and electrons. Previous observations of the Orion Bar suggest that the rotationally excited CH+ and OH correlate with the excited CO, a tracer of dense and warm gas, and formation pumping contributes to CH+ excitation. AIMS Our goal is to examine the spatial distribution of the rotationally excited CH+ and OH emission lines in the Orion Bar in order to establish their physical origin and main formation and excitation mechanisms. METHODS We present spatially sampled maps of the CH+ J=3-2 transition at 119.8 µm and the OH Λ-doublet at 84 µm in the Orion Bar over an area of 110″×110″ with Herschel (PACS). We compare the spatial distribution of these molecules with those of their chemical precursors, C+, O and H2, and tracers of warm and dense gas (high-J CO). We assess the spatial variation of CH+ J=2-1 velocity-resolved line profile at 1669 GHz with Herschel HIFI spectrometer observations. RESULTS The OH and especially CH+ lines correlate well with the high-J CO emission and delineate the warm and dense molecular region at the edge of the Bar. While notably similar, the differences in the CH+ and OH morphologies indicate that CH+ formation and excitation are strongly related to the observed vibrationally excited H2. This, together with the observed broad CH+ line widths, indicates that formation pumping contributes to the excitation of this reactive molecular ion. Interestingly, the peak of the rotationally excited OH 84 µm emission coincides with a bright young object, proplyd 244-440, which shows that OH can be an excellent tracer of UV-irradiated dense gas. CONCLUSIONS The spatial distribution of CH+ and OH revealed in our maps is consistent with previous modeling studies. Both formation pumping and nonreactive collisions in a UV-irradiated dense gas are important CH+ J=3-2 excitation processes. The excitation of the OH Λ-doublet at 84 µm is mainly sensitive to the temperature and density.
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Affiliation(s)
- A Parikka
- Institut d'Astrophysique Spatiale, Université Paris-Saclay, 91405 Orsay Cedex, France; I. Physikalisches Institut der Universität zu Köln, Zülpicher Straße 77, 50937 Köln, Germany
| | - E Habart
- Institut d'Astrophysique Spatiale, Université Paris-Saclay, 91405 Orsay Cedex, France
| | - J Bernard-Salas
- Department of Physical Sciences, The Open University, Milton Keynes MK7 6AA, UK
| | - J R Goicoechea
- Instituto de Ciencia de Materiales de Madrid, CSIC, Sor Juana Inés de la Cruz, 3, 28049 Madrid, Spain
| | - A Abergel
- Institut d'Astrophysique Spatiale, Université Paris-Saclay, 91405 Orsay Cedex, France
| | - P Pilleri
- Université de Toulouse, UPS-OMP, IRAP, 31400 Toulouse, France; CNRS, IRAP, 9 Av. Colonel Roche, BP 44346, 31028 Toulouse Cedex 4, France
| | - E Dartois
- Institut d'Astrophysique Spatiale, Université Paris-Saclay, 91405 Orsay Cedex, France
| | - C Joblin
- Université de Toulouse, UPS-OMP, IRAP, 31400 Toulouse, France; CNRS, IRAP, 9 Av. Colonel Roche, BP 44346, 31028 Toulouse Cedex 4, France
| | - M Gerin
- LERMA, Observatoire de Paris, PSL Research University, Ecole Normale Supérieure, CNRS, 75014 Paris; Sorbonne Universités, UPMC Paris 06, CNRS, LERMA, 75005 Paris
| | - B Godard
- LERMA, Observatoire de Paris, PSL Research University, Ecole Normale Supérieure, CNRS, 75014 Paris; Sorbonne Universités, UPMC Paris 06, CNRS, LERMA, 75005 Paris
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40
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Ji M, Bernard J, Chen L, Brédy R, Ortéga C, Joblin C, Cassimi A, Martin S. Cooling of isolated anthracene cations probed with photons of different wavelengths in the Mini-Ring. J Chem Phys 2017; 146:044301. [PMID: 28147509 DOI: 10.1063/1.4973651] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We report on a direct measurement of the Internal Energy Distribution (IED) shift rate of an initially hot polycyclic aromatic hydrocarbon (PAH) molecular ensemble, anthracene cations (C14H10+). The ions were produced in an electron cyclotron resonance (ECR) ion source and stored in an electrostatic ion storage ring, the Mini-Ring. Laser pulses of two wavelengths were sent successively to merge the stored ion bunch at different storage times to enhance the neutral fragment yield due to fast laser induced dissociation. Using this technique, we have been able to determine directly the energy shift rate of the IED, without involving any theoretical simulation or any assumption on dissociation rates, cooling rates, or the initial IED. Theoretical energy shift rates have been estimated from the evolution of simulated IEDs by taking into account the effects of the unimolecular dissociation and two radiative decay mechanisms: the Poincaré fluorescence and the infrared vibrational emission. The comparison between the experimental results and the model provides new evidence of the important role of the Poincaré fluorescence in the overall cooling process of anthracene cations. Although in the short time range the commonly accepted intuition says that the cooling would result mostly from the dissociation of the hottest ions (depletion cooling), we demonstrate that the Poincaré fluorescence is the dominant contribution (about 85%) to the net cooling effect.
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Affiliation(s)
- M Ji
- Institut Lumière Matière, UMR 5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Cedex Villeurbanne, France
| | - J Bernard
- Institut Lumière Matière, UMR 5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Cedex Villeurbanne, France
| | - L Chen
- Institut Lumière Matière, UMR 5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Cedex Villeurbanne, France
| | - R Brédy
- Institut Lumière Matière, UMR 5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Cedex Villeurbanne, France
| | - C Ortéga
- Institut Lumière Matière, UMR 5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Cedex Villeurbanne, France
| | - C Joblin
- Université de Toulouse; UPS-OMP; IRAP; Toulouse, France
| | - A Cassimi
- CIMAP, CEA/CNRS/ENSICAEN/UNICAEN, Bd H. Becquerel, BP 5133, F-14070 Caen, France
| | - S Martin
- Institut Lumière Matière, UMR 5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Cedex Villeurbanne, France
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41
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Goicoechea JR, Pety J, Cuadrado S, Cernicharo J, Chapillon E, Fuente A, Gerin M, Joblin C, Marcelino N, Pilleri P. Compression and ablation of the photo-irradiated molecular cloud the Orion Bar. Nature 2016; 537:207-209. [PMID: 27509859 PMCID: PMC5111730 DOI: 10.1038/nature18957] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2016] [Accepted: 06/08/2016] [Indexed: 11/26/2022]
Abstract
The Orion Bar is the archetypal edge-on molecular cloud surface illuminated by strong ultraviolet radiation from nearby massive stars. Owing to the close distance to Orion (about 1,350 light-year), the effects of stellar feedback on the parental cloud can be studied in detail. Visible-light observations of the Bar1 show that the transition between the hot ionised gas and the warm neutral atomic gas (the ionisation front) is spatially well separated from the transition from atomic to molecular gas (the dissociation front): about 15 arcseconds or 6,200 astronomical units. (One astronomical unit is the Earth-Sun distance.) Static equilibrium models2,3 used to interpret previous far-infrared and radio observations of the neutral gas in the Bar4,5,6 (typically at 10-20 arcsecond resolution) predict an inhomogeneous cloud structure consisting of dense clumps embedded in a lower density extended gas component. Here we report 1 arcsecond resolution millimetre-wave images that allow us to resolve the molecular cloud surface and constrain the gas density and temperature structures at small spatial scales. In contrast to stationary model predictions7,8,9, there is no appreciable offset between the peak of the H2 vibrational emission (delineating the H/H2 transition) and the edge of the observed CO and HCO+ emission. This implies that the H/H2 and C+/C/CO transition zones are very close. These observations reveal a fragmented ridge of high-density substructures, photo-ablative gas flows and instabilities at the molecular cloud surface. They suggest that the cloud edge has been compressed by a high-pressure wave that currently moves into the molecular cloud. The images demonstrate that dynamical and nonequilibrium effects are important. Thus, they should be included in any realistic description of irradiated interstellar matter.
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Affiliation(s)
- Javier R Goicoechea
- Grupo de Astrofísica Molecular, Instituto de Ciencia de Materiales de Madrid (CSIC), Calle Sor Juana Ines de la Cruz 3, E-28049 Cantoblanco, Madrid, Spain
| | - Jérôme Pety
- Institut de Radioastronomie Millimétrique (IRAM), 300 rue de la Piscine, F-38406 Saint Martin d'Hères, France.,Laboratoire d'Etudes du Rayonnement et de la Matière en Astrophysique et Atmosphères (LERMA), Observatoire de Paris, Centre National de la Recherche Scientifique (CNRS), Unité Mixte de Rechersche (UMR) 8112, École Normale Supérieure, PSL Research University, 24 rue Lhomond, 75231, Paris Cedex 05, France
| | - Sara Cuadrado
- Grupo de Astrofísica Molecular, Instituto de Ciencia de Materiales de Madrid (CSIC), Calle Sor Juana Ines de la Cruz 3, E-28049 Cantoblanco, Madrid, Spain
| | - José Cernicharo
- Grupo de Astrofísica Molecular, Instituto de Ciencia de Materiales de Madrid (CSIC), Calle Sor Juana Ines de la Cruz 3, E-28049 Cantoblanco, Madrid, Spain
| | - Edwige Chapillon
- Institut de Radioastronomie Millimétrique (IRAM), 300 rue de la Piscine, F-38406 Saint Martin d'Hères, France.,Laboratoire d'Astrophysique de Bordeaux (LAB), Université de Bordeaux, UMR 5804, F-33270 Floirac, France.,CNRS, LAB, UMR 5804, F-33270 Floirac, France
| | - Asunción Fuente
- Observatorio Astronómico Nacional (OAN-IGN). Apartado 112, 28803 Alcalá de Henares, Spain
| | - Maryvonne Gerin
- Laboratoire d'Etudes du Rayonnement et de la Matière en Astrophysique et Atmosphères (LERMA), Observatoire de Paris, Centre National de la Recherche Scientifique (CNRS), Unité Mixte de Rechersche (UMR) 8112, École Normale Supérieure, PSL Research University, 24 rue Lhomond, 75231, Paris Cedex 05, France.,Sorbonne Universités, Université Pierre et Marie Curie (UPMC), Université Paris 06, 75000, France
| | - Christine Joblin
- Université de Toulouse, Université Paul-Sabatier-Observatoire Midi-Pyrénées (UPS-OMP), Institut de Recherche en Astrophysique et Planétologie (IRAP), 31028, Toulouse, France.,CNRS, IRAP, 9 Avenue du Colonel Roche, BP 44346, 31028 Toulouse, France
| | - Nuria Marcelino
- Grupo de Astrofísica Molecular, Instituto de Ciencia de Materiales de Madrid (CSIC), Calle Sor Juana Ines de la Cruz 3, E-28049 Cantoblanco, Madrid, Spain
| | - Paolo Pilleri
- Université de Toulouse, Université Paul-Sabatier-Observatoire Midi-Pyrénées (UPS-OMP), Institut de Recherche en Astrophysique et Planétologie (IRAP), 31028, Toulouse, France.,CNRS, IRAP, 9 Avenue du Colonel Roche, BP 44346, 31028 Toulouse, France
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Zhen J, Castillo SR, Joblin C, Mulas G, Sabbah H, Giuliani A, Nahon L, Martin S, Champeaux JP, Mayer PM. VUV photo-processing of PAH cations: quantitative study on the ionization versus fragmentation processes. Astrophys J 2016; 822:113. [PMID: 27212712 PMCID: PMC4872839 DOI: 10.3847/0004-637x/822/2/113] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Interstellar polycyclic aromatic hydrocarbons (PAHs) are strongly affected by the absorption of vacuum ultraviolet (VUV) photons in the interstellar medium (ISM), yet the branching ratio between ionization and fragmentation is poorly studied. This is crucial for the stability and charge state of PAHs in the ISM in different environments, affecting in turn the chemistry, the energy balance, and the contribution of PAHs to the extinction and emission curves. We studied the interaction of PAH cations with VUV photons in the 7 - 20 eV range from the synchrotron SOLEIL beamline, DESIRS. We recorded by action spectroscopy the relative intensities of photo-fragmentation and photo-ionization for a set of eight PAH cations ranging in size from 14 to 24 carbon atoms, with different structures. At photon energies below ~13.6 eV fragmentation dominates for the smaller species, while for larger species ionization is immediately competitive after the second ionization potential (IP). At higher photon energies, all species behave similarly, the ionization yield gradually increases, leveling off between 0.8 and 0.9 at ~18 eV. Among isomers, PAH structure appears to mainly affect the fragmentation cross section, but not the ionization cross section. We also measured the second IP for all species and the third IP for two of them, all are in good agreement with theoretical ones confirming that PAH cations can be further ionized in the diffuse ISM. Determining actual PAH dication abundances in the ISM will require detailed modeling. Our measured photo-ionization yields for several PAH cations provide a necessary ingredient for such models.
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Affiliation(s)
- Junfeng Zhen
- Université de Toulouse, UPS-OMP, Institut de Recherche en Astrophysique et Planétologie, Toulouse, France
- CNRS, IRAP, 9 Av. Colonel Roche, BP 44346, 31028, Toulouse Cedex 4, France
| | - Sarah Rodriguez Castillo
- Université de Toulouse, UPS-OMP, Institut de Recherche en Astrophysique et Planétologie, Toulouse, France
- CNRS, IRAP, 9 Av. Colonel Roche, BP 44346, 31028, Toulouse Cedex 4, France
- Laboratoire de Chimie et Physique Quantiques LCPQ/IRSAMC, Université de Toulouse (UPS) and CNRS, 118 Route de Narbonne, 31062 Toulouse, France
| | - Christine Joblin
- Université de Toulouse, UPS-OMP, Institut de Recherche en Astrophysique et Planétologie, Toulouse, France
- CNRS, IRAP, 9 Av. Colonel Roche, BP 44346, 31028, Toulouse Cedex 4, France
| | - Giacomo Mulas
- Université de Toulouse, UPS-OMP, Institut de Recherche en Astrophysique et Planétologie, Toulouse, France
- CNRS, IRAP, 9 Av. Colonel Roche, BP 44346, 31028, Toulouse Cedex 4, France
- Istituto Nazionale di Astrofisica - Osservatorio Astronomico di Cagliari, via della Scienza 5, 09047 Selargius (CA), Italy
| | - Hassan Sabbah
- Université de Toulouse, UPS-OMP, Institut de Recherche en Astrophysique et Planétologie, Toulouse, France
- CNRS, IRAP, 9 Av. Colonel Roche, BP 44346, 31028, Toulouse Cedex 4, France
| | - Alexandre Giuliani
- Synchrotron SOLEIL, LOrme des Merisiers, 91192 Gif sur Yvette Cedex, France
- INRA, UAR1008 Caractérisation et Elaboration des Produits Issus de l’Agriculture, 44316 Nantes, France
| | - Laurent Nahon
- Synchrotron SOLEIL, LOrme des Merisiers, 91192 Gif sur Yvette Cedex, France
| | - Serge Martin
- Institut Lumière Matière, Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne cedex, France
| | - Jean-Philippe Champeaux
- Laboratoire Collisions Agrégats Réactivité, Université de Toulouse, UPS-IRSAMC, CNRS, 118 Route de Narbonne, Bat 3R1B4, 31062 Toulouse Cedex 9, France
| | - Paul M. Mayer
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa K1N 6N5, Canada
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Abstract
A gas-phase optical spectrum of a large polycyclic aromatic hydrocarbon (PAH) cation - C78H26+- in the 410-610 nm range is presented. This large all-benzenoid PAH should be large enough to be stable with respect to photodissociation in the harsh conditions prevailing in the interstellar medium (ISM). The spectrum is obtained via multi-photon dissociation (MPD) spectroscopy of cationic C78H26 stored in the Fourier Transform Ion Cyclotron Resonance (FT-ICR) cell using the radiation from a mid-band optical parametric oscillator (OPO) laser. The experimental spectrum shows two main absorption peaks at 431 nm and 516 nm, in good agreement with a theoretical spectrum computed via time-dependent density functional theory (TD-DFT). DFT calculations indicate that the equilibrium geometry, with the absolute minimum energy, is of lowered, nonplanar C2 symmetry instead of the more symmetric planar D2h symmetry that is usually the minimum for similar PAHs of smaller size. This kind of slightly broken symmetry could produce some of the fine structure observed in some diffuse interstellar bands (DIBs). It can also favor the folding of C78H26+ fragments and ultimately the formation of fullerenes. This study opens up the possibility to identify the most promising candidates for DIBs amongst large cationic PAHs.
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Affiliation(s)
- Junfeng Zhen
- Université de Toulouse, UPS-OMP, IRAP, Toulouse, France
- CNRS, IRAP, 9 Av. colonel Roche, BP 44346, 31028, Toulouse Cedex 4, France
| | - Giacomo Mulas
- CNRS, IRAP, 9 Av. colonel Roche, BP 44346, 31028, Toulouse Cedex 4, France
- Istituto Nazionale di Astrofisica - Osservatorio Astronomico di Cagliari, via della Scienza 5, 09047 Selargius (CA), Italy
| | - Anthony Bonnamy
- Université de Toulouse, UPS-OMP, IRAP, Toulouse, France
- CNRS, IRAP, 9 Av. colonel Roche, BP 44346, 31028, Toulouse Cedex 4, France
| | - Christine Joblin
- Université de Toulouse, UPS-OMP, IRAP, Toulouse, France
- CNRS, IRAP, 9 Av. colonel Roche, BP 44346, 31028, Toulouse Cedex 4, France
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Cox NLJ, Pilleri P, Berné O, Cernicharo J, Joblin C. Polycyclic aromatic hydrocarbons and molecular hydrogen in oxygen-rich planetary nebulae: the case of NGC 6720. Mon Not R Astron Soc 2016; 456:L89-L93. [PMID: 26924856 PMCID: PMC4765080 DOI: 10.1093/mnrasl/slv184] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Evolved stars are primary sources for the formation of polycyclic aromatic hydrocarbons (PAHs) and dust grains. Their circumstellar chemistry is usually designated as either oxygen-rich or carbon-rich, although dual-dust chemistry objects, whose infrared spectra reveal both silicate- and carbon-dust features, are also known. The exact origin and nature of this dual-dust chemistry is not yet understood. Spitzer-IRS mid-infrared spectroscopic imaging of the nearby, oxygen-rich planetary nebula NGC 6720 reveals the presence of the 11.3 μm aromatic (PAH) emission band. It is attributed to emission from neutral PAHs, since no band is observed in the 7-8 μm range. The spatial distribution of PAHs is found to closely follow that of the warm clumpy molecular hydrogen emission. Emission from both neutral PAHs and warm H2 is likely to arise from photo-dissociation regions associated with dense knots that are located within the main ring. The presence of PAHs together with the previously derived high abundance of free carbon (relative to CO) suggest that the local conditions in an oxygen-rich environment can also become conducive to in-situ formation of large carbonaceous molecules, such as PAHs, via a bottom-up chemical pathway. In this scenario, the same stellar source can enrich the interstellar medium with both oxygen-rich dust and large carbonaceous molecules.
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Affiliation(s)
- N L J Cox
- Université de Toulouse, UPS-OMP, IRAP, 31028, Toulouse, France ; CNRS, IRAP, 9 Av. colonel Roche, BP 44346, F-31028 Toulouse, France
| | - P Pilleri
- Université de Toulouse, UPS-OMP, IRAP, 31028, Toulouse, France ; CNRS, IRAP, 9 Av. colonel Roche, BP 44346, F-31028 Toulouse, France
| | - O Berné
- Université de Toulouse, UPS-OMP, IRAP, 31028, Toulouse, France ; CNRS, IRAP, 9 Av. colonel Roche, BP 44346, F-31028 Toulouse, France
| | - J Cernicharo
- Group of Molecular Astrophysics, ICMM, CSIC, C/Sor Juana Inés de La Cruz N3, E-28049, Madrid, Spain
| | - C Joblin
- Université de Toulouse, UPS-OMP, IRAP, 31028, Toulouse, France ; CNRS, IRAP, 9 Av. colonel Roche, BP 44346, F-31028 Toulouse, France
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Rapacioli M, Simon A, Marshall CCM, Cuny J, Kokkin D, Spiegelman F, Joblin C. Cationic Methylene-Pyrene Isomers and Isomerization Pathways: Finite Temperature Theoretical Studies. J Phys Chem A 2015; 119:12845-54. [PMID: 26600076 DOI: 10.1021/acs.jpca.5b09494] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This paper provides spectral characterizations of the two isomers of the 1-methylenepyrene cation, namely, the 1-pyrenemethylium and a pyrene-like isomer owing a tropylium cycle. Both are possible photodissociation products of the 1-methylpyrene cation and were proposed as potential contributors to the diffuse interstellar bands. In that respect, vibrational and electronic spectra are computed for the optimized structures at the density functional theory (DFT) and time-dependent (TD-)DFT levels. Finite temperature effects on these spectra are estimated from molecular dynamics simulations within the density functional-based tight-binding (DFTB) and TD-DFTB frameworks, these methods being first benchmarked against DFT and TD-DFT calculations. The computed spectra allow discrimination of the two isomers. When the temperature increases, bands are observed to redshift and merge. The isomerization mechanism is investigated with the metadynamics technique, a biased dynamics scheme allowing to probe reaction mechanisms with high energy barriers by investigating the free energy surface at various temperatures. Four pathways with similar barrier heights (3.5-4 eV) are found, showing that the interconversion process would only occur in interstellar clouds under photoactivation. The present study opens the way to simulations on larger methyl- and methylenePAHs of astrophysical interest and their experimental investigation.
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Affiliation(s)
- Mathias Rapacioli
- Laboratoire de Chimie et Physique Quantiques LCPQ/IRSAMC, Université de Toulouse (UPS) and CNRS , 118 Route de Narbonne, F-31062 Toulouse, France
| | - Aude Simon
- Laboratoire de Chimie et Physique Quantiques LCPQ/IRSAMC, Université de Toulouse (UPS) and CNRS , 118 Route de Narbonne, F-31062 Toulouse, France
| | - Charlotte C M Marshall
- Université de Toulouse, UPS-OMP, IRAP , 31400 Toulouse, France.,CNRS, IRAP , 9 Avenue du Colonel Roche, BP 44346-31028 Toulouse Cedex 4, France
| | - Jérôme Cuny
- Laboratoire de Chimie et Physique Quantiques LCPQ/IRSAMC, Université de Toulouse (UPS) and CNRS , 118 Route de Narbonne, F-31062 Toulouse, France
| | - Damian Kokkin
- Université de Toulouse, UPS-OMP, IRAP , 31400 Toulouse, France.,CNRS, IRAP , 9 Avenue du Colonel Roche, BP 44346-31028 Toulouse Cedex 4, France
| | - Fernand Spiegelman
- Laboratoire de Chimie et Physique Quantiques LCPQ/IRSAMC, Université de Toulouse (UPS) and CNRS , 118 Route de Narbonne, F-31062 Toulouse, France
| | - Christine Joblin
- Université de Toulouse, UPS-OMP, IRAP , 31400 Toulouse, France.,CNRS, IRAP , 9 Avenue du Colonel Roche, BP 44346-31028 Toulouse Cedex 4, France
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Pilleri P, Joblin C, Boulanger F, Onaka T. Mixed aliphatic and aromatic composition of evaporating very small grains in NGC 7023 revealed by the 3.4/3.3 μm ratio. Astron Astrophys 2015; 577:A16. [PMID: 26594053 PMCID: PMC4650199 DOI: 10.1051/0004-6361/201425590] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
CONTEXT A chemical scenario was proposed for photon-dominated regions (PDRs) according to which UV photons from nearby stars lead to the evaporation of very small grains (VSGs) and the production of gas-phase polycyclic aromatic hydrocarbons (PAHs). AIMS Our goal is to achieve better insight into the composition and evolution of evaporating very small grains (eVSGs) and PAHs through analyzing the infrared (IR) aliphatic and aromatic emission bands. METHODS We combined spectro-imagery in the near- and mid-IR to study the spatial evolution of the emission bands in the prototypical PDR NGC 7023. We used near-IR spectra obtained with the IRC instrument onboard AKARI to trace the evolution of the 3.3 μm and 3.4 μm bands, which are associated with aromatic and aliphatic C-H bonds on PAHs. The spectral fitting involved an additional broad feature centered at 3.45 μm that is often referred to as the plateau. Mid-IR observations obtained with the IRS instrument onboard the Spitzer Space Telescope were used to distinguish the signatures of eVSGs and neutral and cationic PAHs. We correlated the spatial evolution of all these bands with the intensity of the UV field given in units of the Habing field G0 to explore how their carriers are processed. RESULTS The intensity of the 3.45 μm plateau shows an excellent correlation with that of the 3.3 μm aromatic band (correlation coefficient R = 0.95) and a relatively poor correlation with the aliphatic 3.4 μm band (R=0.77). This indicates that the 3.45 μm feature is dominated by the emission from aromatic bonds. We show that the ratio of the 3.4 μm and 3.3 μm band intensity (I3.4/I3.3) decreases by a factor of 4 at the PDR interface from the more UV-shielded layers (G0 ~ 150, I3.4/I3.3 = 0.13) to the more exposed layers (G0 > 1 × 104, I3.4/I3.3 = 0.03). The intensity of the 3.3 μm band relative to the total neutral PAH intensity shows an overall increase with G0, associated with an increase of both the hardness of the UV field and the H abundance. In contrast, the intensity of the 3.4 μm band relative to the total neutral PAH intensity decreases with G0, showing that their carriers are actively destroyed by UV irradiation and are not efficiently regenerated. The transition region between the aliphatic and aromatic material is found to correspond spatially with the transition zone between neutral PAHs and eVSGs. CONCLUSIONS We conclude that the photo-processing of eVSGs leads to the production of PAHs with attached aliphatic sidegroups that are revealed by the 3.4 μm emission band. Our analysis provides evidence for the presence of very small grains of mixed aromatic and aliphatic composition in PDRs.
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Affiliation(s)
- P Pilleri
- Université de Toulouse; UPS-OMP; IRAP; Toulouse, France ; CNRS; IRAP; 9 Av. colonel Roche, BP 44346, F-31028 Toulouse cedex 4, France
| | - C Joblin
- Université de Toulouse; UPS-OMP; IRAP; Toulouse, France ; CNRS; IRAP; 9 Av. colonel Roche, BP 44346, F-31028 Toulouse cedex 4, France
| | - F Boulanger
- Institut d'Astrophysique Spatiale, 91405, Orsay, France
| | - T Onaka
- Department of Astronomy, Graduate School of Science, University of Tokyo, Tokyo 113-0033, Japan
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47
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Zhen J, Castellanos P, Paardekooper DM, Ligterink N, Linnartz H, Nahon L, Joblin C, Tielens AGGM. LABORATORY PHOTO-CHEMISTRY OF PAHS: IONIZATION VERSUS FRAGMENTATION. Astrophys J Lett 2015; 804:L7. [PMID: 26688710 PMCID: PMC4681094 DOI: 10.1088/2041-8205/804/1/l7] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Interstellar Polycyclic Aromatic Hydrocarbons (PAH) are expected to be strongly processed by Vacuum Ultra-Violet (VUV) photons. Here, we report experimental studies on the ionization and fragmentation of coronene (C24H12), ovalene (C32H14) and hexa-peri-hexabenzocoronene (HBC; C42H18) cations by exposure to synchrotron radiation in the range of 8-40 eV. The results show that for small PAH cations such as coronene, fragmentation (H-loss) is more important than ionization. However, as the size increases, ionization becomes more and more important and for the HBC cation, ionization dominates. These results are discussed and it is concluded that, for large PAHs, fragmentation only becomes important when the photon energy has reached the highest ionization potential accessible. This implies that PAHs are even more photo-stable than previously thought. The implications of this experimental study for the photo-chemical evolution of PAHs in the interstellar medium (ISM) are briefly discussed.
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Affiliation(s)
- Junfeng Zhen
- Leiden Observatory, University of Leiden, P.O. Box 9513, 2300 RA Leiden, The Netherlands ; Sackler Laboratory for Astrophysics, Leiden Observatory, University of Leiden, P.O. Box 9513, 2300 RA Leiden, The Netherlands ; Universitè de Toulouse, UPS-OMP, IRAP, Toulouse, France ; CNRS, IRAP, 9 Av. colonel Roche, BP 44346, 31028, Toulouse Cedex 4, France
| | - Pablo Castellanos
- Leiden Observatory, University of Leiden, P.O. Box 9513, 2300 RA Leiden, The Netherlands ; Sackler Laboratory for Astrophysics, Leiden Observatory, University of Leiden, P.O. Box 9513, 2300 RA Leiden, The Netherlands
| | - Daniel M Paardekooper
- Sackler Laboratory for Astrophysics, Leiden Observatory, University of Leiden, P.O. Box 9513, 2300 RA Leiden, The Netherlands
| | - Niels Ligterink
- Leiden Observatory, University of Leiden, P.O. Box 9513, 2300 RA Leiden, The Netherlands ; Sackler Laboratory for Astrophysics, Leiden Observatory, University of Leiden, P.O. Box 9513, 2300 RA Leiden, The Netherlands
| | - Harold Linnartz
- Sackler Laboratory for Astrophysics, Leiden Observatory, University of Leiden, P.O. Box 9513, 2300 RA Leiden, The Netherlands
| | - Laurent Nahon
- Synchrotron SOLEIL, L'Orme des Merisiers, 91192 Gif sur Yvette Cedex, France
| | - Christine Joblin
- Universitè de Toulouse, UPS-OMP, IRAP, Toulouse, France ; CNRS, IRAP, 9 Av. colonel Roche, BP 44346, 31028, Toulouse Cedex 4, France
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Abstract
Fullerenes have been recently detected in various circumstellar and interstellar environments, raising the question of their formation pathway. It has been proposed that they can form at the low densities found in the interstellar medium by the photo-chemical processing of large polycyclic aromatic hydrocarbons (PAHs). Following our previous work on the evolution of PAHs in the NGC 7023 reflection nebula, we evaluate, using photochemical modeling, the possibility that the PAH C66H20 (i.e. circumovalene) can lead to the formation of C60 upon irradiation by ultraviolet photons. The chemical pathway involves full dehydrogenation of C66H20, folding into a floppy closed cage and shrinking of the cage by loss of C2 units until it reaches the symmetric C60 molecule. At 10" from the illuminating star and with realistic molecular parameters, the model predicts that 100% of C66H20 is converted into C60 in ~ 105 years, a timescale comparable to the age of the nebula. Shrinking appears to be the kinetically limiting step of the whole process. Hence, PAHs larger than C66H20 are unlikely to contribute significantly to the formation of C60, while PAHs containing between 60 and 66 C atoms should contribute to the formation of C60 with shorter timescales, and PAHs containing less than 60 C atoms will be destroyed. Assuming a classical size distribution for the PAH precursors, our model predicts absolute abundances of C60 are up to several 10-4 of the elemental carbon, i.e. less than a percent of the typical interstellar PAH abundance, which is consistent with observational studies. According to our model, once formed, C60 can survive much longer (> 107 years for radiation fields below G0 = 104) than other fullerenes because of the remarkable stability of the C60 molecule at high internal energies. Hence, a natural consequence is that C60 is more abundant than other fullerenes in highly irradiated environments.
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Affiliation(s)
- O Berné
- Université de Toulouse; UPS-OMP; IRAP; Toulouse, France ; CNRS; IRAP; 9 Av. colonel Roche, BP 44346, F-31028 Toulouse cedex 4, France
| | - J Montillaud
- Department of Physics, PO Box 64, University of Helsinki, 00014, Helsinki, Finland ; Institut Utinam, CNRS UMR 6213, OSU THETA, Université de Franche-Comté, 41bis avenue de l'Observatoire, 25000 Besançon, France
| | - C Joblin
- Université de Toulouse; UPS-OMP; IRAP; Toulouse, France ; CNRS; IRAP; 9 Av. colonel Roche, BP 44346, F-31028 Toulouse cedex 4, France
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49
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Bréchignac P, Garcia GA, Falvo C, Joblin C, Kokkin D, Bonnamy A, Parneix P, Pino T, Pirali O, Mulas G, Nahon L. Photoionization of cold gas phase coronene and its clusters: Autoionization resonances in monomer, dimer, and trimer and electronic structure of monomer cation. J Chem Phys 2014; 141:164325. [DOI: 10.1063/1.4900427] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Affiliation(s)
- Philippe Bréchignac
- Institut des Sciences Moléculaires d’Orsay, CNRS UMR8214, Univ Paris-Sud, F-91405 Orsay, France
| | - Gustavo A. Garcia
- Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin, B.P. 48, F-91192 Gif-sur-Yvette, France
| | - Cyril Falvo
- Institut des Sciences Moléculaires d’Orsay, CNRS UMR8214, Univ Paris-Sud, F-91405 Orsay, France
| | - Christine Joblin
- IRAP, Université de Toulouse 3 - CNRS, 9 Av. Colonel Roche, B.P. 44346, F-31028 Toulouse Cedex 4, France
| | - Damian Kokkin
- IRAP, Université de Toulouse 3 - CNRS, 9 Av. Colonel Roche, B.P. 44346, F-31028 Toulouse Cedex 4, France
| | - Anthony Bonnamy
- IRAP, Université de Toulouse 3 - CNRS, 9 Av. Colonel Roche, B.P. 44346, F-31028 Toulouse Cedex 4, France
| | - Pascal Parneix
- Institut des Sciences Moléculaires d’Orsay, CNRS UMR8214, Univ Paris-Sud, F-91405 Orsay, France
| | - Thomas Pino
- Institut des Sciences Moléculaires d’Orsay, CNRS UMR8214, Univ Paris-Sud, F-91405 Orsay, France
| | - Olivier Pirali
- Institut des Sciences Moléculaires d’Orsay, CNRS UMR8214, Univ Paris-Sud, F-91405 Orsay, France
| | - Giacomo Mulas
- INAF - Osservatorio Astronomico di Cagliari, via della scienza 5, I-09047 Selargius (CA), Italy
| | - Laurent Nahon
- Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin, B.P. 48, F-91192 Gif-sur-Yvette, France
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50
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West B, Sit A, Mohamed S, Joblin C, Blanchet V, Bodi A, Mayer PM. Dissociation of the anthracene radical cation: a comparative look at iPEPICO and collision-induced dissociation mass spectrometry results. J Phys Chem A 2014; 118:9870-8. [PMID: 25245634 DOI: 10.1021/jp505438f] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The dissociation of the anthracene radical cation has been studied using two different methods: imaging photoelectron photoion coincidence spectrometry (iPEPCO) and atmospheric pressure chemical ionization-collision induced dissociation mass spectrometry (APCI-CID). Four reactions were investigated: (R1) C14H10(+•) → C14H9(+) + H, (R2) C14H9(+) → C14H8(+•) + H, (R3) C14H10(+•) → C12H8(+•) + C2H2 and (R4) C14H10(+•) → C10H8(+•) + C4H2. An attempt was made to assign structures to each fragment ion, and although there is still room for debate whether for the C12H8(+•) fragment ion is a cyclobuta[b]naphthalene or a biphenylene cation, our modeling results and calculations appear to suggest the more likely structure is cyclobuta[b]naphthalene. The results from the iPEPICO fitting of the dissociation of ionized anthracene are E0 = 4.28 ± 0.30 eV (R1), 2.71 ± 0.20 eV (R2), and 4.20 ± 0.30 eV (average of reaction R3) whereas the Δ(‡)S values (in J K(-1) mol(-1)) are 12 ± 15 (R1), 0 ± 15 (R2), and either 7 ± 10 (using cyclobuta[b]naphthalene ion fragment in reaction R3) or 22 ± 10 (using the biphenylene ion fragment in reaction R3). Modeling of the APCI-CID breakdown diagrams required an estimate of the postcollision internal energy distribution, which was arbitrarily assumed to correspond to a Boltzmann distribution in this study. One goal of this work was to determine if this assumption yields satisfactory energetics in agreement with the more constrained and theoretically vetted iPEPICO results. In the end, it did, with the APCI-CID results being similar.
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Affiliation(s)
- Brandi West
- Chemistry Department, University of Ottawa , Ottawa, Canada K1N 6N5
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