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Monti M, Biancorosso L, Coccia E. Time-Resolved Circular Dichroism in Molecules: Experimental and Theoretical Advances. Molecules 2024; 29:4049. [PMID: 39274897 PMCID: PMC11396666 DOI: 10.3390/molecules29174049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2024] [Revised: 08/22/2024] [Accepted: 08/24/2024] [Indexed: 09/16/2024] Open
Abstract
Following changes in chirality can give access to relevant information on the function or reactivity of molecular systems. Time-resolved circular dichroism (TRCD) spectroscopy proves to be a valid tool to achieve this goal. Depending on the class of molecules, different temporal ranges, spanning from seconds to femtoseconds, need to be investigated to observe such chiroptical changes. Therefore, over the years, several approaches have been adopted to cover the timescale of interest, especially based on pump-probe schemes. Moreover, various theoretical approaches have been proposed to simulate and explain TRCD spectra, including linear and non-linear response methods as well as non-adiabatic molecular dynamics. In this review, an overview on both experimental and theoretical advances in the TRCD field is provided, together with selected applications. A discussion on future theoretical developments for TRCD is also given.
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Affiliation(s)
- Marta Monti
- The Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, 34151 Trieste, Italy
| | - Leonardo Biancorosso
- Dipartimento di Scienze Chimiche e Farmaceutiche, University of Trieste, Via L. Giorgieri 1, 34127 Trieste, Italy
| | - Emanuele Coccia
- Dipartimento di Scienze Chimiche e Farmaceutiche, University of Trieste, Via L. Giorgieri 1, 34127 Trieste, Italy
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2
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Wanie V, Bloch E, Månsson EP, Colaizzi L, Ryabchuk S, Saraswathula K, Ordonez AF, Ayuso D, Smirnova O, Trabattoni A, Blanchet V, Ben Amor N, Heitz MC, Mairesse Y, Pons B, Calegari F. Capturing electron-driven chiral dynamics in UV-excited molecules. Nature 2024; 630:109-115. [PMID: 38778116 PMCID: PMC11153151 DOI: 10.1038/s41586-024-07415-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 04/11/2024] [Indexed: 05/25/2024]
Abstract
Chiral molecules, used in applications such as enantioselective photocatalysis1, circularly polarized light detection2 and emission3 and molecular switches4,5, exist in two geometrical configurations that are non-superimposable mirror images of each other. These so-called (R) and (S) enantiomers exhibit different physical and chemical properties when interacting with other chiral entities. Attosecond technology might enable influence over such interactions, given that it can probe and even direct electron motion within molecules on the intrinsic electronic timescale6 and thereby control reactivity7-9. Electron currents in photoexcited chiral molecules have indeed been predicted to enable enantiosensitive molecular orientation10, but electron-driven chiral dynamics in neutral molecules have not yet been demonstrated owing to the lack of ultrashort, non-ionizing and perturbative light pulses. Here we use time-resolved photoelectron circular dichroism (TR-PECD)11-15 with an unprecedented temporal resolution of 2.9 fs to map the coherent electronic motion initiated by ultraviolet (UV) excitation of neutral chiral molecules. We find that electronic beatings between Rydberg states lead to periodic modulations of the chiroptical response on the few-femtosecond timescale, showing a sign inversion in less than 10 fs. Calculations validate this and also confirm that the combination of the photoinduced chiral current with a circularly polarized probe pulse realizes an enantioselective filter of molecular orientations following photoionization. We anticipate that our approach will enable further investigations of ultrafast electron dynamics in chiral systems and reveal a route towards enantiosensitive charge-directed reactivity.
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Affiliation(s)
- Vincent Wanie
- Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
| | - Etienne Bloch
- Université de Bordeaux - CNRS - CEA, CELIA, UMR5107, Talence, France
| | - Erik P Månsson
- Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - Lorenzo Colaizzi
- Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
- Physics Department, Universität Hamburg, Hamburg, Germany
- Department of Physics, Politecnico di Milano, Milano, Italy
| | - Sergey Ryabchuk
- Physics Department, Universität Hamburg, Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging, Universität Hamburg, Hamburg, Germany
| | - Krishna Saraswathula
- Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
- Physics Department, Universität Hamburg, Hamburg, Germany
| | - Andres F Ordonez
- Department of Physics, Imperial College London, London, UK
- School of Physical and Chemical Sciences, Queen Mary University of London, London, UK
| | - David Ayuso
- Department of Physics, Imperial College London, London, UK
- Max-Born-Institut, Berlin, Germany
- School of Physical and Chemical Sciences, Queen Mary University of London, London, UK
| | - Olga Smirnova
- Max-Born-Institut, Berlin, Germany
- Technische Universität Berlin, Berlin, Germany
| | - Andrea Trabattoni
- Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
- Institute of Quantum Optics, Leibniz Universität Hannover, Hannover, Germany
| | - Valérie Blanchet
- Université de Bordeaux - CNRS - CEA, CELIA, UMR5107, Talence, France
| | - Nadia Ben Amor
- CNRS, UPS, LCPQ (Laboratoire de Chimie et Physique Quantiques), FeRMI, Toulouse, France
| | - Marie-Catherine Heitz
- CNRS, UPS, LCPQ (Laboratoire de Chimie et Physique Quantiques), FeRMI, Toulouse, France
| | - Yann Mairesse
- Université de Bordeaux - CNRS - CEA, CELIA, UMR5107, Talence, France
| | - Bernard Pons
- Université de Bordeaux - CNRS - CEA, CELIA, UMR5107, Talence, France.
| | - Francesca Calegari
- Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
- Physics Department, Universität Hamburg, Hamburg, Germany.
- The Hamburg Centre for Ultrafast Imaging, Universität Hamburg, Hamburg, Germany.
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3
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Rouquet E, Dupont J, Lepere V, Garcia GA, Nahon L, Zehnacker A. Conformer-Selective Photoelectron Circular Dichroism. Angew Chem Int Ed Engl 2024; 63:e202401423. [PMID: 38442011 DOI: 10.1002/anie.202401423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2024] [Revised: 03/04/2024] [Accepted: 03/05/2024] [Indexed: 03/07/2024]
Abstract
Conformational flexibility and chirality both play a key role in molecular recognition. It is therefore very useful to develop spectroscopic methods that simultaneously probe both properties. It has been theoretically predicted that photoelectron circular dichroism (PECD) should be very sensitive to conformational isomerism. However, experimental proof has been less forthcoming and only exists for a very few favorable cases. Here, we present a new PECD scheme based on resonance-enhanced two-photon ionization (RE2PI) using UV/Vis nanosecond laser excitations. The spectral resolution obtained thereby guarantees conformer-selectivity by inducing resonant conformer-specific ππ* S1←S0 transitions. We apply this experimental scheme to the study of chiral 1-indanol, which exists in two conformers linked by a ring inversion and defined by the position of the hydroxyl group, namely axial and equatorial. We show that the PECD of the equatorial and axial forms considerably differ in sign, magnitude and shape. We also discuss the influence of the total ionization energy, vibronic excitation of intermediate and final states, and relative polarization of the excitation and ionization lasers. Conformer-specificity adds a new dimension to the applications of PECD in analytical chemistry addressing now the general case of floppy systems.
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Affiliation(s)
- Etienne Rouquet
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Saclay, F-91405, Orsay, France
- Synchrotron Soleil, L'Orme des Merisiers, St. Aubin BP48, F-91192, Gif sur Yvette, France
| | - Jennifer Dupont
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Saclay, F-91405, Orsay, France
| | - Valeria Lepere
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Saclay, F-91405, Orsay, France
| | - Gustavo A Garcia
- Synchrotron Soleil, L'Orme des Merisiers, St. Aubin BP48, F-91192, Gif sur Yvette, France
| | - Laurent Nahon
- Synchrotron Soleil, L'Orme des Merisiers, St. Aubin BP48, F-91192, Gif sur Yvette, France
| | - Anne Zehnacker
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Saclay, F-91405, Orsay, France
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Sparling C, Ruget A, Ireland L, Kotsina N, Ghafur O, Leach J, Townsend D. The importance of molecular axis alignment and symmetry-breaking in photoelectron elliptical dichroism. J Chem Phys 2023; 159:214301. [PMID: 38038198 DOI: 10.1063/5.0180361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 11/06/2023] [Indexed: 12/02/2023] Open
Abstract
Photoelectron angular distributions (PADs) produced from the photoionization of chiral molecules using elliptically polarized light exhibit a forward/backward asymmetry with respect to the optical propagation direction. By recording these distributions using the velocity-map imaging (VMI) technique, the resulting photoelectron elliptical dichroism (PEELD) has previously been demonstrated as a promising spectroscopic tool for studying chiral molecules in the gas phase. The use of elliptically polarized laser pulses, however, produces PADs (and consequently, PEELD distributions) that do not exhibit cylindrical symmetry about the propagation axis. This leads to significant limitations and challenges when employing conventional VMI acquisition and data processing strategies. Using novel photoelectron image analysis methods based around Hankel transform reconstruction tomography and machine learning, however, we have quantified-for the first time-significant symmetry-breaking contributions to PEELD signals that are of a comparable magnitude to the symmetric terms in the multiphoton ionization of (1R,4R)-(+)- and (1S,4S)-(-)-camphor. This contradicts any assumptions that symmetry-breaking can be ignored when reconstructing VMI data. Furthermore, these same symmetry-breaking terms are expected to appear in any experiment where circular and linear laser fields are used together. This ionization scheme is particularly relevant for investigating dynamics in chiral molecules, but it is not limited to them. Developing a full understanding of these terms and the role they play in the photoionization of chiral molecules is of clear importance if the potential of PEELD and related effects for future practical applications is to be fully realized.
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Affiliation(s)
- Chris Sparling
- Institute of Photonics & Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Alice Ruget
- Institute of Photonics & Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Lewis Ireland
- Institute of Photonics & Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Nikoleta Kotsina
- Institute of Photonics & Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Omair Ghafur
- Institute of Photonics & Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Jonathan Leach
- Institute of Photonics & Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Dave Townsend
- Institute of Photonics & Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
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5
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Svoboda V, Ram NB, Baykusheva D, Zindel D, Waters MDJ, Spenger B, Ochsner M, Herburger H, Stohner J, Wörner HJ. Femtosecond photoelectron circular dichroism of chemical reactions. SCIENCE ADVANCES 2022; 8:eabq2811. [PMID: 35857523 PMCID: PMC9286499 DOI: 10.1126/sciadv.abq2811] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 05/31/2022] [Indexed: 06/15/2023]
Abstract
Understanding the chirality of molecular reaction pathways is essential for a broad range of fundamental and applied sciences. However, the current ability to probe chirality on the time scale of primary processes underlying chemical reactions remains very limited. Here, we demonstrate time-resolved photoelectron circular dichroism (TRPECD) with ultrashort circularly polarized vacuum-ultraviolet (VUV) pulses from a tabletop source. We demonstrate the capabilities of VUV-TRPECD by resolving the chirality changes in time during the photodissociation of atomic iodine from two chiral molecules. We identify several general key features of TRPECD, which include the ability to probe dynamical chirality along the complete photochemical reaction path, the sensitivity to the local chirality of the evolving scattering potential, and the influence of electron scattering off dissociating photofragments. Our results are interpreted by comparison with high-level ab-initio calculations of transient PECDs from molecular photoionization calculations. Our experimental and theoretical techniques define a general approach to femtochirality.
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Affiliation(s)
- Vít Svoboda
- Laboratory of Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
| | - Niraghatam Bhargava Ram
- Laboratory of Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
- Department of Physics, Indian Institute of Science Education and Research–Bhopal, Bhauri, Bhopal 462066, India
| | | | - Daniel Zindel
- Laboratory of Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
| | - Max D. J. Waters
- Laboratory of Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
| | - Benjamin Spenger
- Institute of Chemistry and Biotechnology, Zurich University of Applied Sciences, Wädenswil 8820, Switzerland
| | - Manuel Ochsner
- Laboratory of Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
| | - Holger Herburger
- Laboratory of Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
| | - Jürgen Stohner
- Institute of Chemistry and Biotechnology, Zurich University of Applied Sciences, Wädenswil 8820, Switzerland
| | - Hans Jakob Wörner
- Laboratory of Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
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6
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Schuurman MS, Blanchet V. Time-resolved photoelectron spectroscopy: the continuing evolution of a mature technique. Phys Chem Chem Phys 2022; 24:20012-20024. [PMID: 35297909 DOI: 10.1039/d1cp05885a] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Time-resolved photoelectron spectroscopy (TRPES) has become one of the most widespread techniques for probing nonadiabatic dynamics in the excited electronic states of molecules. Furthermore, the complementary development of ab initio approaches for the simulation of TRPES signals has enabled the interpretation of these transient spectra in terms of underlying coupled electronic-nuclear dynamics. In this perspective, we discuss the current state-of-the-art approaches, including efforts to push femtosecond pulses into vacuum ultraviolet and soft X-ray regimes as well as the utilization of novel polarizations to use time-resolved optical activity as a probe of nonadiabatic dynamics. We close this perspective with a forward-looking prospectus on the new areas of application for this technique.
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Affiliation(s)
- Michael S Schuurman
- National Research Council of Canada, 100 Sussex Dr, Ottawa, ON, K1N 6B9, Canada.,Department of Chemistry and Biomolecular Sciences, University of Ottawa, 10 Marie Curie Dr, Ottawa, ON, Canada.
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7
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Dupont J, Lepère V, Zehnacker A, Hartweg S, Garcia GA, Nahon L. Photoelectron Circular Dichroism as a Signature of Subtle Conformational Changes: The Case of Ring Inversion in 1-Indanol. J Phys Chem Lett 2022; 13:2313-2320. [PMID: 35245057 DOI: 10.1021/acs.jpclett.2c00074] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Chirality plays a fundamental role in the molecular recognition processes. Molecular flexibility is also crucial in molecular recognition, allowing the interacting molecules to adjust their structures and hence optimize the interaction. Methods probing simultaneously chirality and molecular conformation are therefore crucially needed. Taking advantage of a possible control in the gas phase of the conformational distribution between the equatorial and axial conformers resulting from a ring inversion in jet-cooled 1-indanol, we demonstrate here the sensitivity of valence-shell photoelectron circular dichroism (PECD) to both chirality and subtle conformational changes, in a case where the photoelectron spectra of the two conformers are identical. For the highest occupied orbital, we observe a dramatic inversion of the PECD-induced photoelectron asymmetries, while the photoionization cross-section and usual anisotropy (β) parameter are completely insensitive to conformational isomerism. Such a sensitivity is a major asset for the ongoing developments of PECD-based techniques as a sensitive chiral (bio)chemical analytical tool in the gas phase.
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Affiliation(s)
- Jennifer Dupont
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Saclay, F-91405 Orsay, France
| | - Valéria Lepère
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Saclay, F-91405 Orsay, France
| | - Anne Zehnacker
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Saclay, F-91405 Orsay, France
| | - Sebastian Hartweg
- Synchrotron Soleil, L'Orme des Merisiers, St. Aubin BP48, F-91192 Gif sur Yvette, France
| | - Gustavo A Garcia
- Synchrotron Soleil, L'Orme des Merisiers, St. Aubin BP48, F-91192 Gif sur Yvette, France
| | - Laurent Nahon
- Synchrotron Soleil, L'Orme des Merisiers, St. Aubin BP48, F-91192 Gif sur Yvette, France
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Beauvarlet S, Bloch E, Rajak D, Descamps D, Fabre B, Petit S, Pons B, Mairesse Y, Blanchet V. Photoelectron elliptical dichroism spectroscopy of resonance-enhanced multiphoton ionization via the 3s, 3p and 3d Rydberg series in fenchone. Phys Chem Chem Phys 2022; 24:6415-6427. [PMID: 35113091 DOI: 10.1039/d1cp05618b] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The resonance-enhanced multiphoton ionization of chiral molecules by elliptically polarized laser pulses produces photoelectron angular distributions that are forward/backward asymmetric with respect to the light propagation axis. We investigate this photoelectron elliptical dichroism in the (2 + 1)-photon ionization of fenchone molecules, using wavelength tunable femtosecond UV pulses. We show that the photoelectron elliptical asymmetry is extremely sensitive to the intermediate resonant states involved in the ionization process, and enables electronic couplings to be revealed that do not show up so clearly when using circularly polarized light.
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Affiliation(s)
- Sandra Beauvarlet
- Université de Bordeaux - CNRS - CEA, CELIA, UMR 5107, F33405 Talence, France.
| | - Etienne Bloch
- Université de Bordeaux - CNRS - CEA, CELIA, UMR 5107, F33405 Talence, France.
| | - Debobrata Rajak
- Université de Bordeaux - CNRS - CEA, CELIA, UMR 5107, F33405 Talence, France.
| | - Dominique Descamps
- Université de Bordeaux - CNRS - CEA, CELIA, UMR 5107, F33405 Talence, France.
| | - Baptiste Fabre
- Université de Bordeaux - CNRS - CEA, CELIA, UMR 5107, F33405 Talence, France.
| | - Stéphane Petit
- Université de Bordeaux - CNRS - CEA, CELIA, UMR 5107, F33405 Talence, France.
| | - Bernard Pons
- Université de Bordeaux - CNRS - CEA, CELIA, UMR 5107, F33405 Talence, France.
| | - Yann Mairesse
- Université de Bordeaux - CNRS - CEA, CELIA, UMR 5107, F33405 Talence, France.
| | - Valérie Blanchet
- Université de Bordeaux - CNRS - CEA, CELIA, UMR 5107, F33405 Talence, France.
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Lee HG, Ranecky ST, Vasudevan S, Ladda N, Rosen T, Das S, Ghosh J, Braun H, Reich DM, Senftleben A, Baumert T. Pulse length dependence of photoelectron circular dichroism. Phys Chem Chem Phys 2022; 24:27483-27494. [DOI: 10.1039/d2cp03202c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We investigated photoelectron circular dichroism (PECD) using pulses with various durations. From the experiment with fenchone, we found constancy of the PECD over a wide range of pulse durations and estimated lifetimes of internal conversions.
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Affiliation(s)
- Han-gyeol Lee
- Institut für Physik, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - Simon T. Ranecky
- Institut für Physik, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - Sudheendran Vasudevan
- Institut für Physik, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - Nicolas Ladda
- Institut für Physik, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - Tonio Rosen
- Institut für Physik, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - Sagnik Das
- Institut für Physik, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - Jayanta Ghosh
- Institut für Physik, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - Hendrike Braun
- Institut für Physik, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - Daniel M. Reich
- Dahlem Center for Complex Quantum Systems and Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany
| | - Arne Senftleben
- Institut für Physik, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - Thomas Baumert
- Institut für Physik, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
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