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González D, Canosa A, Martínez-Núñez E, Fernández-Ramos A, Ballesteros B, Agúndez M, Cernicharo J, Jiménez E. Effect of temperature on the gas-phase reaction of CH 3CN with OH radicals: experimental ( T = 11.7-177.5 K) and computational ( T = 10-400 K) kinetic study. Phys Chem Chem Phys 2024; 26:3632-3646. [PMID: 38224163 DOI: 10.1039/d3cp04944b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2024]
Abstract
Acetonitrile (CH3CN) is present in the interstellar medium (ISM) in a variety of environments. However, at the ultracold temperatures of the ISM, radical-molecule reactions are not widely investigated because of the experimental handicap of getting organic molecules in the gas phase by conventional techniques. The CRESU (French acronym for Reaction Kinetics in a Uniform Supersonic Flow) technique solves this problem. For this reason, we present in this work the kinetic study of the gas-phase reaction of CH3CN with one of the most ubiquitous radicals, the hydroxyl (OH) radical, as a function of temperature (11.7-177.5 K). The kinetic technique employed to investigate the CH3CN + OH reaction was the pulsed laser photolysis-laser induced fluorescence. The rate coefficient for this reaction k(T) has been observed to drastically increase from 177.5 K to 107.0 K (about 2 orders of magnitude), while the increase in k(T) from 107.0 K to 11.7 K was milder (around 4 times). The temperature dependent expressions for k(T) are provided in the two distinct T-ranges, excluding the upper limit obtained for k(177.5 K): In addition, the rate coefficients estimated by the canonical competitive unified statistical (CCUS) theory show a similar behaviour to the experimental results, when evaluated within the high-pressure limit. This is consistent with the experimentally observed independence of k(T) with total gas density at selected temperatures. Astrochemical networks, such as the KIDA database or UMIST, do not include the CH3CN + OH reaction as a potential depletion process for acetonitrile in the ISM because the current studies predict very low rate coefficients at IS temperatures. According to the model (T = 10 K), the impact of the titled reaction on the abundances of CH3CN appears to be negligible in dark molecular clouds of the ISM (∼1% of the total depletion reactions included in UMIST network). With respect to the potential formation of the CH2CN radical in those environments, even in the most favourable scenario, where this radical could be formed in a 100% yield from the CH3CN + OH reaction, this route would only contribute around 2% to the current assumed formation routes by the UMIST network.
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Affiliation(s)
- Daniel González
- Departamento de Química Física, Facultad de Ciencias y Tecnologías Químicas, Universidad de Castilla-La Mancha (UCLM), Avda. Camilo José Cela 1B, 13071 Ciudad Real, Spain.
- Instituto de Investigación en Combustión y Contaminación Atmosférica, UCLM, Camino de Moledores s/n, 13071 Ciudad Real, Spain
| | - André Canosa
- Institut de Physique de Rennes-CNRS - UMR 6251, Université de Rennes, F-35000 Rennes, France
| | - Emilio Martínez-Núñez
- Departamento de Química Física, Facultade de Química, Campus Vida, Universidade de Santiago de Compostela, Avda. das Ciencias s/n, 15782, Santiago de Compostela, Spain.
| | - Antonio Fernández-Ramos
- Departamento de Química Física, Facultade de Química, Campus Vida, Universidade de Santiago de Compostela, Avda. das Ciencias s/n, 15782, Santiago de Compostela, Spain.
- Centro Singular de Investigación en Química Biológica y Materiales Moleculares (CIQUS), Campus Vida, Universidade de Santiago de Compostela, C/Jenaro de la Fuente s/n, 15782, Santiago de Compostela, Spain
| | - Bernabé Ballesteros
- Departamento de Química Física, Facultad de Ciencias y Tecnologías Químicas, Universidad de Castilla-La Mancha (UCLM), Avda. Camilo José Cela 1B, 13071 Ciudad Real, Spain.
- Instituto de Investigación en Combustión y Contaminación Atmosférica, UCLM, Camino de Moledores s/n, 13071 Ciudad Real, Spain
| | - Marcelino Agúndez
- Molecular Astrophysics Group, Instituto de Física Fundamental (IFF-CSIC), Consejo Superior de Investigaciones Científicas, C/Serrano 123, 28006, Madrid, Spain
| | - José Cernicharo
- Molecular Astrophysics Group, Instituto de Física Fundamental (IFF-CSIC), Consejo Superior de Investigaciones Científicas, C/Serrano 123, 28006, Madrid, Spain
| | - Elena Jiménez
- Departamento de Química Física, Facultad de Ciencias y Tecnologías Químicas, Universidad de Castilla-La Mancha (UCLM), Avda. Camilo José Cela 1B, 13071 Ciudad Real, Spain.
- Instituto de Investigación en Combustión y Contaminación Atmosférica, UCLM, Camino de Moledores s/n, 13071 Ciudad Real, Spain
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González D, Lema-Saavedra A, Espinosa S, Martínez-Núñez E, Fernández-Ramos A, Canosa A, Ballesteros B, Jiménez E. Reaction of OH radicals with CH 3NH 2 in the gas phase: experimental (11.7-177.5 K) and computed rate coefficients (10-1000 K). Phys Chem Chem Phys 2022; 24:23593-23601. [PMID: 36134502 DOI: 10.1039/d2cp03414j] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Nitrogen-bearing molecules, like methylamine (CH3NH2), can be the building blocks of amino acids in the interstellar medium (ISM). At the ultralow temperatures of the ISM, it is important to know its gas-phase reactivity towards interstellar radicals and the products formed. In this work, the kinetics of the OH + CH3NH2 reaction was experimentally and theoretically investigated at low- and high-pressure limits (LPL and HPL) between 10 and 1000 K. Moreover, the CH2NH2 and CH3NH yields were computed in the same temperature range for both pressure regimes. A pulsed CRESU (French acronym for Reaction Kinetics in a Uniform Supersonic Flow) apparatus was employed to determine the rate coefficient, k(T), in the 11.7-177.5 K range. A drastic increase of k(T) when the temperature is lowered was observed in agreement with theoretical calculations, evaluated by the competitive canonical unified statistical (CCUS) theory, below 300 K in the LPL regime. The same trend was observed in the HPL regime below 350 K, but the theoretical k(T) values were higher than the experimental ones. Above 200 K, the calculated rate coefficients are improved with respect to previous computational studies and are in excellent agreement with the experimental literature data. In the LPL, the formation of CH3NH becomes largely dominant below ca. 100 K. Conversely, in the HPL regime, CH2NH2 is the only product below 100 K, whereas CH3NH becomes dominant at 298 K with a branching ratio similar to the one found in the LPL regime (≈70%). At T > 300 K, both reaction channels are competitive independently of the pressure regime.
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Affiliation(s)
- Daniel González
- Departamento de Química Física, Facultad de Ciencias y Tecnologías Químicas, Universidad de Castilla-La Mancha, Avda. Camilo José Cela 1b, 13071, Ciudad Real, Spain.
| | - Anxo Lema-Saavedra
- Centro Singular de Investigación en Química Biológica y Materiales Moleculares (CIQUS), Campus Vida, Universidade de Santiago de Compostela, C/Jenaro de la Fuente s/n, 15782, Santiago de Compostela, Spain.
| | - Sara Espinosa
- Departamento de Química Física, Facultad de Ciencias y Tecnologías Químicas, Universidad de Castilla-La Mancha, Avda. Camilo José Cela 1b, 13071, Ciudad Real, Spain.
| | - Emilio Martínez-Núñez
- Departamento de Química Física, Facultade de Química, Campus Vida, Universidade de Santiago de Compostela, Avda. das Ciencias s/n, 15782, Santiago de Compostela, Spain
| | - Antonio Fernández-Ramos
- Centro Singular de Investigación en Química Biológica y Materiales Moleculares (CIQUS), Campus Vida, Universidade de Santiago de Compostela, C/Jenaro de la Fuente s/n, 15782, Santiago de Compostela, Spain. .,Departamento de Química Física, Facultade de Química, Campus Vida, Universidade de Santiago de Compostela, Avda. das Ciencias s/n, 15782, Santiago de Compostela, Spain
| | - André Canosa
- CNRS, IPR (Institut de Physique de Rennes)-UMR 6251, Université de Rennes, F-35000 Rennes, France
| | - Bernabé Ballesteros
- Departamento de Química Física, Facultad de Ciencias y Tecnologías Químicas, Universidad de Castilla-La Mancha, Avda. Camilo José Cela 1b, 13071, Ciudad Real, Spain. .,Instituto de Investigación en Combustión y Contaminación Atmosférica (ICCA), Universidad de Castilla-La Mancha, Camino de Moledores s/n, 13071, Ciudad Real, Spain
| | - Elena Jiménez
- Departamento de Química Física, Facultad de Ciencias y Tecnologías Químicas, Universidad de Castilla-La Mancha, Avda. Camilo José Cela 1b, 13071, Ciudad Real, Spain. .,Instituto de Investigación en Combustión y Contaminación Atmosférica (ICCA), Universidad de Castilla-La Mancha, Camino de Moledores s/n, 13071, Ciudad Real, Spain
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3
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Durif O, Capron M, Messinger JP, Benidar A, Biennier L, Bourgalais J, Canosa A, Courbe J, Garcia GA, Gil JF, Nahon L, Okumura M, Rutkowski L, Sims IR, Thiévin J, Le Picard SD. A new instrument for kinetics and branching ratio studies of gas phase collisional processes at very low temperatures. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:014102. [PMID: 33514236 DOI: 10.1063/5.0029991] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 12/16/2020] [Indexed: 06/12/2023]
Abstract
A new instrument dedicated to the kinetic study of low-temperature gas phase neutral-neutral reactions, including clustering processes, is presented. It combines a supersonic flow reactor with vacuum ultra-violet synchrotron photoionization time-of-flight mass spectrometry. A photoion-photoelectron coincidence detection scheme has been adopted to optimize the particle counting efficiency. The characteristics of the instrument are detailed along with its capabilities illustrated through a few results obtained at low temperatures (<100 K) including a photoionization spectrum of n-butane, the detection of formic acid dimer formation, and the observation of diacetylene molecules formed by the reaction between the C2H radical and C2H2.
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Affiliation(s)
- O Durif
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France
| | - M Capron
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France
| | - J P Messinger
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
| | - A Benidar
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France
| | - L Biennier
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France
| | - J Bourgalais
- LATMOS/IPSL, UVSQ, Université Paris-Saclay, UPMC, Univ Paris 06, CNRS, 78280 Guyancourt, France
| | - A Canosa
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France
| | - J Courbe
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France
| | - G A Garcia
- Synchrotron SOLEIL, L'orme des Merisiers, BP48 St Aubin, 91192 Gif Sur Yvette Cedex, France
| | - J F Gil
- Synchrotron SOLEIL, L'orme des Merisiers, BP48 St Aubin, 91192 Gif Sur Yvette Cedex, France
| | - L Nahon
- Synchrotron SOLEIL, L'orme des Merisiers, BP48 St Aubin, 91192 Gif Sur Yvette Cedex, France
| | - M Okumura
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
| | - L Rutkowski
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France
| | - I R Sims
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France
| | - J Thiévin
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France
| | - S D Le Picard
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France
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Gas phase reaction kinetics of complex organic molecules at temperatures of the interstellar medium: The OH + CH3OH case. ACTA ACUST UNITED AC 2020. [DOI: 10.1017/s1743921319006446] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
AbstractRecent experimental and theoretical works concerning gas-phase radical-neutral reactions involving Complex Organic Molecules are reviewed in the context of cold interstellar objects with a special emphasis on the OH + CH3OH reaction and its potential impact on the formation of CH3O.
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Blázquez S, González D, Neeman EM, Ballesteros B, Agúndez M, Canosa A, Albaladejo J, Cernicharo J, Jiménez E. Gas-phase kinetics of CH 3CHO with OH radicals between 11.7 and 177.5 K. Phys Chem Chem Phys 2020; 22:20562-20572. [PMID: 32966434 PMCID: PMC7116299 DOI: 10.1039/d0cp03203d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Gas-phase reactions in the interstellar medium (ISM) are a source of molecules in this environment. The knowledge of the rate coefficient for neutral-neutral reactions as a function of temperature, k(T), is essential to improve astrochemical models. In this work, we have experimentally measured k(T) for the reaction between the OH radical and acetaldehyde, both present in many sources of the ISM. Laser techniques coupled to a CRESU system were used to perform the kinetic measurements. The obtained modified Arrhenius equation is k(T = 11.7-177.5 K) = (1.2 ± 0.2) × 10-11 (T/300 K)-(1.8±0.1) exp-{(28.7 ± 2.5)/T} cm3 molecule-1 s-1. The k(T) value of the title reaction has been measured for the first time below 60 K. No pressure dependence of k(T) was observed at ca. 21, 50, 64 and 106 K. Finally, a pure gas-phase model indicates that the title reaction could become the main CH3CO formation pathway in dark molecular clouds, assuming that CH3CO is the main reaction product at 10 K.
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Affiliation(s)
- Sergio Blázquez
- Departamento de Química Física, Facultad de Ciencias y Tecnologías Químicas, Universidad de Castilla-La Mancha, Avda. Camilo José Cela 1B, 13071, Ciudad Real, Spain.
| | - Daniel González
- Departamento de Química Física, Facultad de Ciencias y Tecnologías Químicas, Universidad de Castilla-La Mancha, Avda. Camilo José Cela 1B, 13071, Ciudad Real, Spain.
| | - Elias M Neeman
- Departamento de Química Física, Facultad de Ciencias y Tecnologías Químicas, Universidad de Castilla-La Mancha, Avda. Camilo José Cela 1B, 13071, Ciudad Real, Spain.
| | - Bernabé Ballesteros
- Departamento de Química Física, Facultad de Ciencias y Tecnologías Químicas, Universidad de Castilla-La Mancha, Avda. Camilo José Cela 1B, 13071, Ciudad Real, Spain. and Instituto de Investigación en Combustión y Contaminación Atmosférica (ICCA), Universidad de Castilla-La Mancha, Camino de Moledores s/n, 13071, Ciudad Real, Spain
| | - Marcelino Agúndez
- Molecular Astrophysics Group, Instituto de Física Fundamental (IFF-CSIC), Consejo Superior de Investigaciones Científicas, C/Serrano 123, 28006, Madrid, Spain
| | - André Canosa
- CNRS, IPR (Institut de Physique de Rennes)-UMR 6251, Université de Rennes, F-35000 Rennes, France
| | - José Albaladejo
- Departamento de Química Física, Facultad de Ciencias y Tecnologías Químicas, Universidad de Castilla-La Mancha, Avda. Camilo José Cela 1B, 13071, Ciudad Real, Spain. and Instituto de Investigación en Combustión y Contaminación Atmosférica (ICCA), Universidad de Castilla-La Mancha, Camino de Moledores s/n, 13071, Ciudad Real, Spain
| | - José Cernicharo
- Molecular Astrophysics Group, Instituto de Física Fundamental (IFF-CSIC), Consejo Superior de Investigaciones Científicas, C/Serrano 123, 28006, Madrid, Spain
| | - Elena Jiménez
- Departamento de Química Física, Facultad de Ciencias y Tecnologías Químicas, Universidad de Castilla-La Mancha, Avda. Camilo José Cela 1B, 13071, Ciudad Real, Spain. and Instituto de Investigación en Combustión y Contaminación Atmosférica (ICCA), Universidad de Castilla-La Mancha, Camino de Moledores s/n, 13071, Ciudad Real, Spain
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6
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Zeinalipour-Yazdi CD, Lam K. Linear correlation of vertical ionization energies and partial charges on acetaldehyde and methyl formate radicals in various solvents. Chem Phys Lett 2020. [DOI: 10.1016/j.cplett.2020.137311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Bulut N, Aguado A, Sanz-Sanz C, Roncero O. Quantum Effects on the D + H 3+ → H 2D + + H Deuteration Reaction and Isotopic Variants. J Phys Chem A 2019; 123:8766-8775. [PMID: 31545608 DOI: 10.1021/acs.jpca.9b06081] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The title reaction and its isotopic variants are studied using quasi-classical trajectory (QCT) (without taking into account corrections to account for the possible zero point energy breakdown) and ring polymer molecular dynamics (RPMD) methods with a full dimensional and accurate potential energy surface which presents an exchange barrier of approximately 0.144 eV. The QCT rate constant increases when the temperature decreases from 1500 to 10 K. On the contrary, the RPMD rate constant decreases with decreasing temperature, in semiquantitative agreement with recent experimental results. The present RPMD results are in between the thermal and translational experimental rate constants, extracted from the measured data to eliminate the initial vibrational excitation of H3+, obtained in an arc discharge. The difference between the present RPMD results and experimental values is attributed to the possible existence of non thermal vibrational excitation of H3+, not completely removed by the semiempirical model used for the analysis of the experimental results. Also, it is found that, below 200 K, the RPMD trajectories are trapped, forming long-lived collision complexes, with lifetimes longer than 1 ns. These collision complexes can fragment by either redissociating back to reactants or react to products, in the two cases tunneling through the centrifugal and reaction barriers, respectively. The contribution of the formation of the complex to the total deuteration rate should be calculated with more accurate quantum methods, as has been found recently for reactions of larger systems, and the present four atoms system is a good candidate to benchmark the adequacy of RPMD method at temperatures below 100 K.
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Affiliation(s)
- Niyazi Bulut
- Department of Physics , Firat University , 23169 Elazig , Turkey
| | - Alfredo Aguado
- Unidad Asociada UAM-IFF-CSIC, Departamento de Química Física Aplicada, Facultad de Ciencias, Módulo 14 , Universidad Autónoma de Madrid , 28049 , Madrid , Spain
| | - Cristina Sanz-Sanz
- Unidad Asociada UAM-IFF-CSIC, Departamento de Química Física Aplicada, Facultad de Ciencias, Módulo 14 , Universidad Autónoma de Madrid , 28049 , Madrid , Spain
| | - Octavio Roncero
- Instituto de Física Fundamental (IFF-CSIC), C.S.I.C. , Serrano 123 , 28006 Madrid , Spain
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Blázquez S, González D, García-Sáez A, Antiñolo M, Bergeat A, Caralp F, Mereau R, Canosa A, Ballesteros B, Albaladejo J, Jiménez E. Experimental and theoretical investigation on the OH + CH 3C(O)CH 3 reaction at interstellar temperatures (T=11.7-64.4 K). ACS EARTH & SPACE CHEMISTRY 2019; 3:1873-1883. [PMID: 31799490 PMCID: PMC6887536 DOI: 10.1021/acsearthspacechem.9b00144] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The rate coefficient, k(T), for the gas-phase reaction between OH radicals and acetone CH3C(O)CH3, has been measured using the pulsed CRESU (French acronym for Reaction Kinetics in a Uniform Supersonic Flow) technique (T = 11.7-64.4 K). The temperature dependence of k(T = 10-300 K) has also been computed using a RRKM-Master equation analysis after partial revision of the potential energy surface. In agreement with previous studies we found that the reaction proceeds via initial formation of two pre-reactive complexes both leading to H2O + CH3C(O)CH2 by H-abstraction tunneling. The experimental k(T) was found to increase as temperature was lowered. The measured values have been found to be several orders of magnitude higher than k(300 K). This trend is reproduced by calculations, with a special good agreement with experiments below 25 K. The effect of total gas density on k(T) has been explored. Experimentally, no pressure dependence of k(20 K) and k(64 K) was observed, while k(50 K) at the largest gas density 4.47×1017 cm-3 is twice higher than the average values found at lower densities. The computed k(T) is also reported for 103 cm-3 of He (representative of the interstellar medium). The predicted rate coefficients at 10 K surround the experimental value which appears to be very close to the low pressure regime prevailing in the interstellar medium. For gas-phase model chemistry of interstellar molecular clouds, we suggest using the calculated value of 1.8×10-10 cm3 molecule-1 s-1 at 10 K and the reaction products are water and CH3C(O)CH2 radicals.
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Affiliation(s)
- Sergio Blázquez
- Departamento de Química Física. Facultad de Ciencias y Tecnologías Químicas. Universidad de Castilla-La Mancha, Avda. Camilo José Cela, 1B. 13071 Ciudad Real, Spain
| | - Daniel González
- Departamento de Química Física. Facultad de Ciencias y Tecnologías Químicas. Universidad de Castilla-La Mancha, Avda. Camilo José Cela, 1B. 13071 Ciudad Real, Spain
| | - Alberto García-Sáez
- Departamento de Química Física. Facultad de Ciencias y Tecnologías Químicas. Universidad de Castilla-La Mancha, Avda. Camilo José Cela, 1B. 13071 Ciudad Real, Spain
| | - María Antiñolo
- Instituto de Investigación en Combustión y Contaminación Atmosférica (ICCA). Universidad de Castilla-La Mancha, Camino de Moledores s/n. 13071 Ciudad Real, Spain
| | - Astrid Bergeat
- Univ. Bordeaux, CNRS, Bordeaux INP, ISM, UMR 5255, F-33405 Talence, France
| | - Françoise Caralp
- Univ. Bordeaux, CNRS, Bordeaux INP, ISM, UMR 5255, F-33405 Talence, France
| | - Raphaël Mereau
- Univ. Bordeaux, CNRS, Bordeaux INP, ISM, UMR 5255, F-33405 Talence, France
| | - André Canosa
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France
| | - Bernabé Ballesteros
- Departamento de Química Física. Facultad de Ciencias y Tecnologías Químicas. Universidad de Castilla-La Mancha, Avda. Camilo José Cela, 1B. 13071 Ciudad Real, Spain
- Instituto de Investigación en Combustión y Contaminación Atmosférica (ICCA). Universidad de Castilla-La Mancha, Camino de Moledores s/n. 13071 Ciudad Real, Spain
| | - José Albaladejo
- Departamento de Química Física. Facultad de Ciencias y Tecnologías Químicas. Universidad de Castilla-La Mancha, Avda. Camilo José Cela, 1B. 13071 Ciudad Real, Spain
- Instituto de Investigación en Combustión y Contaminación Atmosférica (ICCA). Universidad de Castilla-La Mancha, Camino de Moledores s/n. 13071 Ciudad Real, Spain
| | - Elena Jiménez
- Departamento de Química Física. Facultad de Ciencias y Tecnologías Químicas. Universidad de Castilla-La Mancha, Avda. Camilo José Cela, 1B. 13071 Ciudad Real, Spain
- Instituto de Investigación en Combustión y Contaminación Atmosférica (ICCA). Universidad de Castilla-La Mancha, Camino de Moledores s/n. 13071 Ciudad Real, Spain
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9
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Naumkin F, del Mazo-Sevillano P, Aguado A, Suleimanov YV, Roncero O. Zero- and high-pressure mechanisms in the complex forming reactions of OH with methanol and formaldehyde at low temperatures. ACS EARTH & SPACE CHEMISTRY 2019; 3:1158-1169. [PMID: 31511842 PMCID: PMC6739233 DOI: 10.1021/acsearthspacechem.9b00051] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
A recent Ring Polymer Molecular Dynamics study of the reactions of OH with methanol and formaldehyde, at zero pressure and below 100 K, has shown the formation of long lived complexes, with long lifetimes, longer than 100 ns for the lower temperatures studied, 20-100 K (del Mazo-Sevillano et al., 2019). These long lifetimes support the existence of multi collision events with the He buffer-gas atoms under experimental conditions, as suggested by several transition state theory studies of these reactions. In this work we study these secondary collisions, as a dynamical approach to study pressure effects on these reactions. For this purpose, the potential energy surfaces of He with H2CO, OH, H2O and HCO are calculated at highly accurate ab initio level. The stability of some of the complexes is studied using Path Integral Molecular dynamics techniques, determining that OH-H2CO complexes can be formed up to 100 K or higher temperatures, while the weaker He-H2CO complexes dissociate at approximately 50 K. The predicted IR intensity spectra shows new features which could help the identification of the OH-H2CO complex. Finally, the He-H2CO + OH and OH-H2CO + He collisions are studied using quassi-classical trajectories, finding that the cross section to produce HCO + H2O products increases with decreasing collision energy, and that it is ten times higher in the He-H2CO + OH case.
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Affiliation(s)
| | - Pablo del Mazo-Sevillano
- Unidad Asociada UAM-IFF-CSIC, Departamento de Química Física Aplicada, Facultad de Ciencias Módulo 14, Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Alfredo Aguado
- Unidad Asociada UAM-IFF-CSIC, Departamento de Química Física Aplicada, Facultad de Ciencias Módulo 14, Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Yury V. Suleimanov
- Computation-based Science and Technology Research Center, Cyprus Institute, 20 Kavafi Str., Nicosia 2121, Cyprus
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, Massachusetts 02139, United States
| | - Octavio Roncero
- Instituto de Física Fundamental (IFF-CSIC), C.S.I.C., Serrano 123, 28006 Madrid, Spain
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10
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Watanabe N, Sato K, Takahashi M. Electron momentum spectroscopy study on the valence electronic structure of methyl formate. J Chem Phys 2019; 150:194306. [PMID: 31117792 DOI: 10.1063/1.5097201] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We report an electron momentum spectroscopy study on methyl formate. A symmetric noncoplanar (e, 2e) experiment has been performed at an incident electron energy of 1.2 keV and electron momentum profiles of the valence orbitals have been obtained. On the basis of the result, assignments of the 10a'-1 and 1a″-1 bands have been made to resolve a contradiction between photoelectron spectroscopy and Penning ionization electron spectroscopy studies. Comparisons between experiment and theory reveal that the influence of the molecular vibration has to be taken into account for a proper understanding of the electron momentum profiles. Contributions of individual vibrational normal modes have also been investigated in detail by means of the harmonic analytical quantum mechanical approach.
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Affiliation(s)
- Noboru Watanabe
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan
| | - Kimihiro Sato
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan
| | - Masahiko Takahashi
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan
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11
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del Mazo-Sevillano P, Aguado A, Jiménez E, Suleimanov YV, Roncero O. Quantum Roaming in the Complex-Forming Mechanism of the Reactions of OH with Formaldehyde and Methanol at Low Temperature and Zero Pressure: A Ring Polymer Molecular Dynamics Approach. J Phys Chem Lett 2019; 10:1900-1907. [PMID: 30939028 PMCID: PMC6534501 DOI: 10.1021/acs.jpclett.9b00555] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The quantum dynamics of the title reactions are studied using the ring polymer molecular dynamics (RPMD) method from 20 to 1200 K using recently proposed full dimensional potential energy surfaces which include long-range dipole-dipole interactions. A V-shaped dependence of the reaction rate constants is found with a minimum at 200-300 K, in rather good agreement with the current experimental data. For temperatures above 300 K the reaction proceeds following a direct H-abstraction mechanism. However, below 100 K the reaction proceeds via organic-molecule···OH collision complexes, with very long lifetimes, longer than 10-7 s, associated with quantum roaming arising from the inclusion of quantum effects by the use of RPMD. The long lifetimes of these complexes are comparable to the time scale of the tunnelling to form reaction products. These complexes are formed at zero pressure because of quantum effects and not only at high pressure as suggested by transition state theory (TST) calculations for OH + methanol and other OH reactions. The zero-pressure rate constants reproduce quite well measured ones below 200 K, and this agreement opens the question of how important the pressure effects on the reaction rate constants are, as implied in TST-like formalisms. The zero-pressure mechanism is applicable only to very low gas density environments, such as the interstellar medium, which are not repeatable by experiments.
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Affiliation(s)
- Pablo del Mazo-Sevillano
- Unidad Asociada UAM-CSIC, Departamento de Química Física Aplicada, Facultad de Ciencias M-14, Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Alfredo Aguado
- Unidad Asociada UAM-CSIC, Departamento de Química Física Aplicada, Facultad de Ciencias M-14, Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Elena Jiménez
- Departamento de Química Física, Facultad de Ciencias y Tecnologías Químicas, Universidad de Castilla La Mancha, Avda. Camilo José Cela 1B, 13071 Ciudad Real, Spain
- Instituto de Investigación en Combustión y Contaminación Atmosférica, Universidad de Castilla La Mancha, Camino de Moledores s/n, 13071 Ciudad Real, Spain
| | - Yury V. Suleimanov
- Computation-based Science and Technology Research Center, Cyprus Institute, 20 Kavafi Str., Nicosia 2121, Cyprus
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, Massachusetts 02139, United States
| | - Octavio Roncero
- Instituto de Física Fundamental (IFF-CSIC), C.S.I.C., Serrano 123, 28006 Madrid, Spain
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12
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Ocaña AJ, Blázquez S, Potapov A, Ballesteros B, Canosa A, Antiñolo M, Vereecken L, Albaladejo J, Jiménez E. Gas-phase reactivity of CH 3OH toward OH at interstellar temperatures (11.7-177.5 K): experimental and theoretical study. Phys Chem Chem Phys 2019; 21:6942-6957. [PMID: 30868151 DOI: 10.1039/c9cp00439d] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reactivity of methanol (CH3OH) toward the hydroxyl (OH) radical was investigated in the temperature range 11.7-177.5 K using the CRESU (French acronym for Reaction Kinetics in a Uniform Supersonic Flow) technique. In the present study, the temperature dependence of the rate coefficient for the OH + CH3OH reaction, k(T), has been revisited and additional experimental and computational data are reported. New kinetic measurements were performed to fill the existing gaps (<22 K, 22-42 K and 88-123 K), reporting k(T < 20 K) for the first time. The lowest temperature ever achieved by a pulsed CRESU has been obtained in this work (11.7 K). k(T) abruptly increases by almost 2 orders of magnitude from 177.5 K to around 100 K. At T < 100 K, this increase is less pronounced, reaching the capture limit at temperatures below 22 K. The pressure dependence of k(T) has been investigated for selected temperatures and gas densities (1.5 × 1016 to 4.3 × 1017 cm-3), combining our results with those previously reported. No dependence was observed within the experimental uncertainties below 110 K. The high- and low-pressure rate coefficients, kHPL(T) and kLPL(T), were also studied in detail using high-level quantum chemical and theoretical kinetic methodologies, closely reproducing the experimental data between 20 and 400 K. The results suggest that the experimental data are near the high pressure limit at the lowest temperatures, but that the reaction remains a fast and effective source of CH2OH and CH3O at the low pressures and temperatures prevalent in the interstellar medium.
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Affiliation(s)
- Antonio J Ocaña
- Departamento de Química Física, Facultad de Ciencias y Tecnologías Químicas, Universidad de Castilla-La Mancha, Avda. Camilo José Cela, 1B, 13071 Ciudad Real, Spain.
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13
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Heard DE. Rapid Acceleration of Hydrogen Atom Abstraction Reactions of OH at Very Low Temperatures through Weakly Bound Complexes and Tunneling. Acc Chem Res 2018; 51:2620-2627. [PMID: 30358991 DOI: 10.1021/acs.accounts.8b00304] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A generally accepted principle of chemical kinetics is that a reaction will be very slow at low temperatures if there is an activation barrier on the potential energy surface to form products. However, this Account shows that the reverse is true for gas-phase hydrogen abstraction reactions of the hydroxyl radical, OH, with organic molecules with which it can form a weakly bound (5-30 kJ mol-1) hydrogen-bonded complex. For hydrogen atom abstraction reactions of OH with volatile organic compounds (VOCs) containing alcohol, ether, carbonyl, and ester functional groups, the reaction accelerates rapidly at very low temperatures, with rate coefficients, k, that can be up to a 1000 times faster than those at room temperature, despite the barrier to products. The OH radical is a crucial intermediate in Earth's atmosphere, combustion processes, and the chemistry of the interstellar medium, where temperatures can reach as low as 10 K, so this behavior has very important implications for gas-phase chemistry in space. The key point is that at low temperatures the lifetime of the OH-VOC complex against re-dissociation back to reactants becomes much longer, and hence the probability of quantum mechanical tunneling under the reaction barrier to form products becomes much higher. These observations were made possible by using Laval nozzles to generate uniform supersonic flows at extremely low temperatures so that condensation of the reagents at reactor walls is avoided. In this Account, the use of laser flash-photolysis combined with laser-induced fluorescence spectroscopy within Laval flows is described to study the unusual kinetics of this type of reaction at temperatures down to 21 K and demonstrate the rapid upturn in the rate coefficient. For the reaction of OH with CH3OH, further evidence for the precomplex and tunneling mechanism comes from observation of the CH3O reaction product at very low temperatures, despite it being formed over the higher barrier to reaction. The experimental observations are supported by theoretical calculations using the MESMER master equation package to calculate k( T) and product yields as a function of temperature and which make use of potential energy surfaces determined using ab initio methods. The CH3O product is formed over a narrower barrier with a larger imaginary frequency and is calculated to be the sole product at very low temperatures. The kinetics of the OH reaction with CH3OH were measured to be independent of pressure, consistent with a tunneling mechanism rather than any collisional stabilization of the prereactive complex. In this Account, we collate available kinetic data and show that this newly discovered mechanism for H atom transfer reactions appears to be generally applicable for reactions of OH with organic molecules containing oxygenated functional groups, which have been observed in space by radio-astronomy. Rather than being ignored for a range of interstellar environments, these OH reactions are now being included in chemical networks in space and have been shown to significantly influence the abundance of OH, the organic molecules themselves, and reaction products and provide novel routes to forming even more complex functional groups, for example, precursors to prebiotic molecules.
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Affiliation(s)
- Dwayne E. Heard
- School of Chemistry and National Centre for Atmospheric Science, University of Leeds, Leeds LS2 9JT, United Kingdom
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14
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Roncero O, Zanchet A, Aguado A. Low temperature reaction dynamics for CH 3OH + OH collisions on a new full dimensional potential energy surface. Phys Chem Chem Phys 2018; 20:25951-25958. [PMID: 30294740 PMCID: PMC6290987 DOI: 10.1039/c8cp04970j] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Is the rise of the rate constant measured in laval expansion experiments of OH with organic molecules at low temperatures due to the reaction between the reactants or due to the formation of complexes with the buffer gas? This question has importance for understanding the evolution of prebiotic molecules observed in different astrophysical objects. Among these molecules methanol is one of the most widely observed, and its reaction with OH has been studied by several groups showing a fast increase in the rate constant under 100 K. Transition state theory doesn't reproduce this behavior and here dynamical calculations are performed on a new full dimensional potential energy surface developed for this purpose. The calculated classical reactive cross sections show an increase at low collision energies due to a complex forming mechanism. However, the calculated rate constant at temperatures below 100 K remains lower than the observed one. Quantum effects are likely responsible for the measured behavior at low temperatures.
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Affiliation(s)
- Octavio Roncero
- Instituto de Física Fundamental (IFF-CSIC), C.S.I.C., Serrano 123, Madrid 28006, Spain.
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15
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Ocaña AJ, Blázquez S, Ballesteros B, Canosa A, Antiñolo M, Albaladejo J, Jiménez E. Gas phase kinetics of the OH + CH 3CH 2OH reaction at temperatures of the interstellar medium (T = 21-107 K). Phys Chem Chem Phys 2018; 20:5865-5873. [PMID: 29417104 PMCID: PMC5975950 DOI: 10.1039/c7cp07868d] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ethanol, CH3CH2OH, has been unveiled in the interstellar medium (ISM) by radioastronomy and it is thought to be released into the gas phase after the warm-up phase of the grain surface, where it is formed. Once in the gas phase, it can be destroyed by different reactions with atomic and radical species, such as hydroxyl (OH) radicals. The knowledge of the rate coefficients of all these processes at temperatures of the ISM is essential in the accurate interpretation of the observed abundances. In this work, we have determined the rate coefficient for the reaction of OH with CH3CH2OH (k(T)) between 21 and 107 K by employing the pulsed and continuous CRESU (Cinétique de Réaction en Ecoulement Supersonique Uniforme, which means Reaction Kinetics in a Uniform Supersonic Flow) technique. The pulsed laser photolysis technique was used for generating OH radicals, whose time evolution was monitored by laser induced fluorescence. An increase of approximately 4 times was observed for k(21 K) with respect to k(107 K). With respect to k(300 K), the OH-reactivity at 21 K is enhanced by two orders of magnitude. The obtained T-expression in the investigated temperature range is k(T) = (2.1 ± 0.5) × 10-11 (T/300 K)-(0.71±0.10) cm3 molecule-1 s-1. In addition, the pressure dependence of k(T) has been investigated at several temperatures between 21 K and 90 K. No pressure dependence of k(T) was observed in the investigated ranges. This may imply that this reaction is purely bimolecular or that the high-pressure limit is reached at the lowest total pressure experimentally accessible in our system. From our results, k(T) at usual IS temperatures (∼10-100 K) is confirmed to be very fast. Typical rate coefficients can be considered to range within about 4 × 10-11 cm3 molecule-1 s-1 at 100 K and around 1 × 10-10 cm3 molecule-1 s-1 at 20 K. The extrapolation of k at the lowest temperatures of the dense molecular clouds of ISM is also discussed in this paper.
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Affiliation(s)
- A J Ocaña
- Departamento de Química Física. Facultad de Ciencias y Tecnologías Químicas. Universidad de Castilla-La Mancha, Avda. Camilo José Cela, 1B, 13071 Ciudad Real, Spain.
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16
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Sleiman C, El Dib G, Rosi M, Skouteris D, Balucani N, Canosa A. Low temperature kinetics and theoretical studies of the reaction CN + CH 3NH 2: a potential source of cyanamide and methyl cyanamide in the interstellar medium. Phys Chem Chem Phys 2018; 20:5478-5489. [PMID: 29082409 DOI: 10.1039/c7cp05746f] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reaction between cyano radicals (which are ubiquitous in interstellar clouds) and methylamine (a molecule detected in various interstellar sources) has been investigated in a synergistic experimental and theoretical study. The reaction has been found to be very fast in the entire range of temperatures investigated (23-297 K) by using a CRESU apparatus coupled to pulsed laser photolysis - laser induced fluorescence. The global experimental rate coefficient is given by In addition, dedicated electronic structure calculations of the underlying potential energy surface have been performed, together with capture theory and RRKM calculations. The experimental data have been interpreted in the light of the theoretical calculations and the product branching ratio has been established. According to the present study, in the range of temperatures investigated the title reaction is an efficient interstellar route of formation of cyanamide, NH2CN, another interstellar species. The second most important channel is the one leading to methyl cyanamide, CH3NHCN (an isomer of aminoacetonitrile), via a CN/H exchange mechanism with a yield of 12% of the global reaction in the entire range of temperatures explored. For a possible inclusion in future astrochemical models we suggest, by referring to the usual expression the following values: α = 3.68 × 10-12 cm3 molec-1 s-1, β = -1.80, γ = 7.79 K for the channel leading to NH2CN + CH3; α = 5.05 × 10-13 cm3 molec-1 s-1, β = -1.82, γ = 7.93 K for the channel leading to CH3NHCN + H.
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Affiliation(s)
- Chantal Sleiman
- Institut de Physique de Rennes, UMR 6251 du CNRS - Université de Rennes 1, Bat. 11C, Campus de Beaulieu, 263 Avenue du Général Leclerc, F-35042 Rennes Cedex, France.
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17
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Wu J, Ning H, Ma L, Ren W. Pressure-dependent kinetics of methyl formate reactions with OH at combustion, atmospheric and interstellar temperatures. Phys Chem Chem Phys 2018; 20:26190-26199. [DOI: 10.1039/c8cp04114h] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Pressure dependence occurs in bimolecular hydrogen abstraction reactions at combustion, atmospheric and interstellar temperatures.
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Affiliation(s)
- Junjun Wu
- Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong
- New Territories
- Hong Kong
| | - Hongbo Ning
- Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong
- New Territories
- Hong Kong
- Shenzhen Research Institute, The Chinese University of Hong Kong
- New Territories
| | - Liuhao Ma
- Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong
- New Territories
- Hong Kong
| | - Wei Ren
- Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong
- New Territories
- Hong Kong
- Shenzhen Research Institute, The Chinese University of Hong Kong
- New Territories
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18
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Ocaña AJ, Jiménez E, Ballesteros B, Canosa A, Antiñolo M, Albaladejo J, Agúndez M, Cernicharo J, Zanchet A, del Mazo P, Roncero O, Aguado A. Is the gas-phase OH+H 2CO reaction a source of HCO in interstellar cold dark clouds? A kinetic, dynamic and modelling study. THE ASTROPHYSICAL JOURNAL 2017; 850:28. [PMID: 29880977 PMCID: PMC5988043 DOI: 10.3847/1538-4357/aa93d9] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Chemical kinetics of neutral-neutral gas-phase reactions at ultralow temperatures is a fascinating research subject with important implications on the chemistry of complex organic molecules in the interstellar medium (T∼10-100K). Scarce kinetic information is currently available for this kind of reactions at T<200 K. In this work we use the CRESU (Cinétique de Réaction en Ecoulement Supersonique Uniforme, which means Reaction Kinetics in a Uniform Supersonic Flow) technique to measure for the first time the rate coefficients (k) of the gas-phase OH+H2CO reaction between 22 and 107 K. k values greatly increase from 2.1×10-11 cm3 s-1 at 107 K to 1.2×10-10 cm3 s-1 at 22 K. This is also confirmed by quasi-classical trajectories (QCT) at collision energies down to 0.1 meV performed using a new full dimension and ab initio potential energy surface, recently developed which generates highly accurate potential and includes long range dipole-dipole interactions. QCT calculations indicate that at low temperatures HCO is the exclusive product for the OH+H2CO reaction. In order to revisit the chemistry of HCO in cold dense clouds, k is reasonably extrapolated from the experimental results at 10K (2.6×10-10 cm3 s-1). The modeled abundances of HCO are in agreement with the observations in cold dark clouds for an evolving time of 105-106 yrs. The different sources of production of HCO are presented and the uncertainties in the chemical networks discussed. This reaction can be expected to be a competitive process in the chemistry of prestellar cores. The present reaction is shown to account for a few percent of the total HCO production rate. Extensions to photodissociation regions and diffuse clouds environments are also commented.
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Affiliation(s)
- A. J. Ocaña
- Departamento de Química Física. Facultad de Ciencias y Tecnologías Químicas. Universidad de Castilla-La Mancha. Avda. Camilo José Cela 1B. 13071, Ciudad Real, Spain
| | - E. Jiménez
- Departamento de Química Física. Facultad de Ciencias y Tecnologías Químicas. Universidad de Castilla-La Mancha. Avda. Camilo José Cela 1B. 13071, Ciudad Real, Spain
- Instituto de Investigación en Combustión y Contaminación Atmosférica. Universidad de Castilla-La Mancha. Camino de Moledores s/n. 13071, Ciudad Real, Spain
| | - B. Ballesteros
- Departamento de Química Física. Facultad de Ciencias y Tecnologías Químicas. Universidad de Castilla-La Mancha. Avda. Camilo José Cela 1B. 13071, Ciudad Real, Spain
- Instituto de Investigación en Combustión y Contaminación Atmosférica. Universidad de Castilla-La Mancha. Camino de Moledores s/n. 13071, Ciudad Real, Spain
| | - A. Canosa
- Institut de Physique de Rennes, UMR 6251 CNRS-Université de Rennes 1. Campus de Beaulieu, Bât 11C, 263 Av. Général Leclerc, 35042, Rennes, France
| | - M. Antiñolo
- Instituto de Investigación en Combustión y Contaminación Atmosférica. Universidad de Castilla-La Mancha. Camino de Moledores s/n. 13071, Ciudad Real, Spain
| | - J. Albaladejo
- Departamento de Química Física. Facultad de Ciencias y Tecnologías Químicas. Universidad de Castilla-La Mancha. Avda. Camilo José Cela 1B. 13071, Ciudad Real, Spain
- Instituto de Investigación en Combustión y Contaminación Atmosférica. Universidad de Castilla-La Mancha. Camino de Moledores s/n. 13071, Ciudad Real, Spain
| | - M. Agúndez
- Instituto de Ciencia de Materiales de Madrid. Consejo Superior de Investigaciones Científicas. C/ Sor Juana Inés de la Cruz, 3. 28049, Cantoblanco, Madrid, Spain
| | - J. Cernicharo
- Instituto de Ciencia de Materiales de Madrid. Consejo Superior de Investigaciones Científicas. C/ Sor Juana Inés de la Cruz, 3. 28049, Cantoblanco, Madrid, Spain
| | - A. Zanchet
- Instituto de Física Fundamental, CSIC, C/ Serrano, 123, 28006 Madrid, Spain
| | - P. del Mazo
- Instituto de Física Fundamental, CSIC, C/ Serrano, 123, 28006 Madrid, Spain
| | - O. Roncero
- Instituto de Física Fundamental, CSIC, C/ Serrano, 123, 28006 Madrid, Spain
| | - A. Aguado
- Departamento de Química Física Aplicada (UAM), Unidad Asociada IFF-CSIC, Facultad de Ciencias C-XIV, Universidad Autónoma de Madrid, 28049, Madrid, Spain
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19
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Potapov A, Canosa A, Jiménez E, Rowe B. Chemie mit Überschall: 30 Jahre astrochemische Forschung und künftige Herausforderungen. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201611240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Alexey Potapov
- Laborastrophysikgruppe des Max-Planck-Instituts für Astronomie am Institut für Festkörperphysik; Friedrich-Schiller-Universität Jena; Helmholtzweg 3 07743 Jena Deutschland
| | - André Canosa
- Département de Physique Moléculaire; Institut de Physique de Rennes, UMR CNRS-UR1 6251, Université de Rennes 1, Campus de Beaulieu; 263 Avenue du Général Leclerc 35042 Rennes Cedex Frankreich
| | - Elena Jiménez
- Departamento de Química Física, Facultad de Ciencias y Tecnologías Químicas; Universidad de Castilla-La Mancha; Avda. Camilo José Cela, 1B 13071 Ciudad Real Spanien
| | - Bertrand Rowe
- Rowe-consulting, 22 Chemin des Moines; 22750 Saint Jacut de la Mer Frankreich
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20
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Potapov A, Canosa A, Jiménez E, Rowe B. Uniform Supersonic Chemical Reactors: 30 Years of Astrochemical History and Future Challenges. Angew Chem Int Ed Engl 2017; 56:8618-8640. [DOI: 10.1002/anie.201611240] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 01/27/2017] [Indexed: 11/06/2022]
Affiliation(s)
- Alexey Potapov
- Laborastrophysikgruppe des Max-Planck-Instituts für Astronomie am Institut für Festkörperphysik; Friedrich-Schiller-Universität Jena; Helmholtzweg 3 07743 Jena Germany
| | - André Canosa
- Département de Physique Moléculaire; Institut de Physique de Rennes, UMR CNRS-UR1 6251, Université de Rennes 1, Campus de Beaulieu; 263 Avenue du Général Leclerc 35042 Rennes Cedex France
| | - Elena Jiménez
- Departamento de Química Física, Facultad de Ciencias y Tecnologías Químicas; Universidad de Castilla-La Mancha; Avda. Camilo José Cela, 1B 13071 Ciudad Real Spain
| | - Bertrand Rowe
- Rowe-consulting, 22 Chemin des Moines; 22750 Saint Jacut de la Mer France
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21
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Hickson KM, Loison JC, Nuñez-Reyes D, Méreau R. Quantum Tunneling Enhancement of the C + H2O and C + D2O Reactions at Low Temperature. J Phys Chem Lett 2016; 7:3641-3646. [PMID: 27574866 DOI: 10.1021/acs.jpclett.6b01637] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Recent studies of neutral gas-phase reactions characterized by barriers show that certain complex forming processes involving light atoms are enhanced by quantum mechanical tunneling at low temperature. Here, we performed kinetic experiments on the activated C((3)P) + H2O reaction, observing a surprising reactivity increase below 100 K, an effect that is only partially reproduced when water is replaced by its deuterated analogue. Product measurements of H- and D-atom formation allowed us to quantify the contribution of complex stabilization to the total rate while confirming the lower tunneling efficiency of deuterium. This result, which is validated through statistical calculations of the intermediate complexes and transition states has important consequences for simulated interstellar water abundances and suggests that tunneling mechanisms could be ubiquitous in cold dense clouds.
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Affiliation(s)
- Kevin M Hickson
- University Bordeaux, ISM, CNRS UMR 5255, F-33400 Talence, France
| | | | | | - Raphaël Méreau
- University Bordeaux, ISM, CNRS UMR 5255, F-33400 Talence, France
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22
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Reactivity of OH and CH 3OH Between 22 and 64 K: Modelling the Gas Phase Production of CH 3O in Barnard 1B. ACTA ACUST UNITED AC 2016; 823. [PMID: 27279655 DOI: 10.3847/0004-637x/823/1/25] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In the last years, ultra-low temperature chemical kinetic experiments have demonstrated that some gas-phase reactions are much faster than previously thought. One example is the reaction between OH and CH3OH, which has been recently found to be accelerated at low temperatures yielding CH3O as main product. This finding opened the question of whether the CH3O observed in the dense core Barnard 1b could be formed by the gas-phase reaction of CH3OH and OH. Several chemical models including this reaction and grain-surface processes have been developed to explain the observed abundance of CH3O with little success. Here we report for the first time rate coefficients for the gas-phase reaction of OH and CH3OH down to a temperature of 22 K, very close to those in cold interstellar clouds. Two independent experimental set-ups based on the supersonic gas expansion technique coupled to the pulsed laser photolysis-laser induced fluorescence technique were used to determine rate coefficients in the temperature range 22-64 K. The temperature dependence obtained in this work can be expressed as k(22-64 K) = (3.6 ± 0.1) × 10-12(T/300 K)-(1.0±0.2) cm3 molecule-1 s-1. Implementing this expression in a chemical model of a cold dense cloud results in CH3O/CH3OH abundance ratios similar or slightly lower than the value of ∼ 3 × 10-3 observed in Barnard 1b. This finding confirms that the gas-phase reaction between OH and CH3OH is an important contributor to the formation of interstellar CH3O. The role of grain-surface processes in the formation of CH3O, although it cannot be fully neglected, remains controversial.
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Sleiman C, González S, Klippenstein SJ, Talbi D, El Dib G, Canosa A. Pressure dependent low temperature kinetics for CN + CH3CN: competition between chemical reaction and van der Waals complex formation. Phys Chem Chem Phys 2016; 18:15118-32. [DOI: 10.1039/c6cp01982j] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The gas phase reaction between the CN radical and acetonitrile CH3CN was investigated experimentally with a CRESU apparatus and a slow flow reactor as well as theoretically to explore the temperature and pressure dependence of its rate coefficient from 354 K down to 23 K.
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Affiliation(s)
- Chantal Sleiman
- Département de Physique Moléculaire
- Institut de Physique de Rennes
- UMR 6251 du CNRS - Université de Rennes 1
- Bat. 11C
- Campus de Beaulieu
| | - Sergio González
- Departamento de Química Física
- Facultad de Ciencias y Tecnologías Químicas
- Universidad de Castilla La Mancha
- Campus Universitario
- 13071 Ciudad Real
| | | | - Dahbia Talbi
- Laboratoire Univers et Particules de Montpellier – UMR 5299 du CNRS - Université de Montpellier
- Campus Triolet
- 34095 Montpellier Cedex 05
- France
| | - Gisèle El Dib
- Département de Physique Moléculaire
- Institut de Physique de Rennes
- UMR 6251 du CNRS - Université de Rennes 1
- Bat. 11C
- Campus de Beaulieu
| | - André Canosa
- Département de Physique Moléculaire
- Institut de Physique de Rennes
- UMR 6251 du CNRS - Université de Rennes 1
- Bat. 11C
- Campus de Beaulieu
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