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Desrousseaux B, Konings M, Loreau J, Lique F. HD-H + collisions: statistical and quantum state-to-state studies. Phys Chem Chem Phys 2021; 23:19202-19208. [PMID: 34524315 DOI: 10.1039/d1cp02564c] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In the early Universe, the cooling mechanisms of the gas significantly rely on the HD abundance and excitation conditions. A proper modeling of its formation and destruction paths as well as its excitation by both radiative and collisional processes is then required to accurately describe the cooling mechanisms of the pristine gas. In such media, ion-molecule reactions are dominant. Their theoretical study is challenging and state-of-the-art quantum time-independent methods are computationally limited to collisions involving light molecules. Here, we report a state-to-state scattering study of the HD-H+ collisional system using two different methods: an exact quantum time-independent approach and a recently developed fast and efficient statistical method. Reactive and inelastic rate coefficients were obtained for temperatures up to 300 K. The statistical method is able to reproduce exact calculations with an accuracy reaching the astrophysical needs while drastically reducing the computational resources requirements. Such results suggest that this new statistical method should be considered to provide the astrophysical community collisional data for which quantum calculations are impossible.
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Affiliation(s)
- Benjamin Desrousseaux
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France.
| | - Maarten Konings
- KU Leuven, Department of Chemistry, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Jérôme Loreau
- KU Leuven, Department of Chemistry, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - François Lique
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France.
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2
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Temperature dependence of the rate coefficient of formation of CN radical from C + NH. Chem Phys Lett 2021. [DOI: 10.1016/j.cplett.2021.138493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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3
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Bowen KP, Hillenbrand PM, Liévin J, Savin DW, Urbain X. Dynamics of the isotope exchange reaction of D with H 3 +, H 2D +, and D 2H . J Chem Phys 2021; 154:084307. [PMID: 33639774 DOI: 10.1063/5.0038434] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We have measured the merged-beams rate coefficient for the titular isotope exchange reactions as a function of the relative collision energy in the range of ∼3 meV-10 eV. The results appear to scale with the number of available sites for deuteration. We have performed extensive theoretical calculations to characterize the zero-point energy corrected reaction path. Vibrationally adiabatic minimum energy paths were obtained using a combination of unrestricted quadratic configuration interaction of single and double excitations and internally contracted multireference configuration interaction calculations. The resulting barrier height, ranging from 68 meV to 89 meV, together with the various asymptotes that may be reached in the collision, was used in a classical over-the-barrier model. All competing endoergic reaction channels were taken into account using a flux reduction factor. This model reproduces all three experimental sets quite satisfactorily. In order to generate thermal rate coefficients down to 10 K, the internal excitation energy distribution of each H3 + isotopologue is evaluated level by level using available line lists and accurate spectroscopic parameters. Tunneling is accounted for by a direct inclusion of the exact quantum tunneling probability in the evaluation of the cross section. We derive a thermal rate coefficient of <1×10-12 cm3 s-1 for temperatures below 44 K, 86 K, and 139 K for the reaction of D with H3 +, H2D+, and D2H+, respectively, with tunneling effects included. The derived thermal rate coefficients exceed the ring polymer molecular dynamics prediction of Bulut et al. [J. Phys. Chem. A 123, 8766 (2019)] at all temperatures.
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Affiliation(s)
- K P Bowen
- Columbia Astrophysics Laboratory, Columbia University, New York, New York 10027, USA
| | - P-M Hillenbrand
- Columbia Astrophysics Laboratory, Columbia University, New York, New York 10027, USA
| | - J Liévin
- Spectroscopy, Quantum Chemistry and Atmospheric Remote Sensing (SQUARES), Université Libre de Bruxelles, B-1050 Brussels, Belgium
| | - D W Savin
- Columbia Astrophysics Laboratory, Columbia University, New York, New York 10027, USA
| | - X Urbain
- Institute of Condensed Matter and Nanosciences, Université Catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium
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4
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Garcia E, Jambrina PG, Laganà A. Kinetics Of The H + CH 2 → CH + H 2 Reaction At Low Temperature. J Phys Chem A 2019; 123:7408-7419. [PMID: 31373813 DOI: 10.1021/acs.jpca.9b06212] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A quasiclassical trajectory study of the kinetics of the title astrochemical reaction in a range of temperatures varying from 5 to 1000 K (corresponding to both the outer and the inner regions of the protostar and the circumstellar envelopes) was carried out and a clear dependence of the rate coefficient on the temperature is given, in contrast with the constant value adopted in kinetics astrochemical databases. Levering the massive nature of the performed calculations and of the detailed dynamical investigation of the reactive process, a rationalization of the temperature dependence of the released translational energy and of the rovibrational population of the CH and H2 diatomic products is also provided. Furthermore, the effect of the initial rovibrational energy of CH2 on the state-specific rate coefficients and cross sections is analyzed in order to single out the role played by the different regions of the potential energy surface on the dynamical outcomes and on the modeling the temperature dependence of the reactive efficiency of the investigated process. This led to a parametrization of the computed rate in terms of the following double Arrhenius expression (in cm3 s-1), k(T) = 2.50 × 10-10 exp(- 1.67/T) + 5.98 × 10-11 exp(- 280.5/T), alternative to the piecewise formulation into the three subintervals of temperature in which the overall 5-1000 K interval can be divided.
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Affiliation(s)
- Ernesto Garcia
- Departamento de Química Física , Universidad del País Vasco (UPV/EHU) , Paseo de la Universidad 7 , 01006 Vitoria , Spain
| | - Pablo G Jambrina
- Departamento de Química Física , Universidad de Salamanca , Plaza de los Caı́dos , 37008 Salamanca , Spain
| | - Antonio Laganà
- UOS Perugia , CNR ISTM , via Elce di sotto 8 , I-06123 Perugia , Italy.,Master UP srl , Strada Sperandio 15 , I-06125 Perugia , Italy
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5
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Bhowmick S, Bossion D, Scribano Y, Suleimanov YV. The low temperature D + + H 2→ HD + H + reaction rate coefficient: a ring polymer molecular dynamics and quasi-classical trajectory study. Phys Chem Chem Phys 2018; 20:26752-26763. [PMID: 30324962 DOI: 10.1039/c8cp05398g] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reaction between D+ and H2 plays an important role in astrochemistry at low temperatures and also serves as a prototype for a simple ion-molecule reaction. Its ground X[combining tilde]1A' state has a very small thermodynamic barrier (up to 1.8 × 10-2 eV) and the reaction proceeds through the formation of an intermediate complex lying within the potential well with a depth of at least 0.2 eV, thus representing a challenge for dynamical studies. In the present work, we analyze the title reaction within the temperature range of 20-100 K by means of ring polymer molecular dynamics (RPMD) and quasi-classical trajectory (QCT) methods over the full-dimensional global potential energy surface developed by Aguado et al. [A. Aguado, O. Roncero, C. Tablero, C. Sanz and M. Paniagua, J. Chem. Phys., 2000, 112, 1240]. The computed thermal RPMD and QCT rate coefficients are found to be almost independent of temperature and fall within the range of 1.34-2.01 × 10-9 cm3 s-1. They are also in very good agreement with previous time-independent quantum mechanical and statistical quantum method calculations. Furthermore, we observe that the choice of asymptotic separation distance between the reactants can markedly alter the rate coefficient in the low temperature regime (20-50 K). Therefore it is of utmost importance to correctly assign the value of this parameter for dynamical studies, particularly at very low temperatures of astrochemical importance. We finally conclude that the experimental rate measurements for the title reaction are highly desirable in future.
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Affiliation(s)
- Somnath Bhowmick
- Computation-based Science and Technology Research Center, The Cyprus Institute, 20 Konstantinou Kavafi Street, Nicosia 2121, Cyprus.
| | - Duncan Bossion
- Laboratoire Univers et Particules de Montpellier, UMR-CNRS 5299, Université de Montpellier, Place Eugène Bataillon, 34095 Montpellier, France
| | - Yohann Scribano
- Laboratoire Univers et Particules de Montpellier, UMR-CNRS 5299, Université de Montpellier, Place Eugène Bataillon, 34095 Montpellier, France
| | - Yury V Suleimanov
- Computation-based Science and Technology Research Center, The Cyprus Institute, 20 Konstantinou Kavafi Street, Nicosia 2121, Cyprus.
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Jambrina PG, Menéndez M, Aoiz FJ. Angular momentum-scattering angle quantum correlation: a generalized deflection function. Chem Sci 2018; 9:4837-4850. [PMID: 29910936 PMCID: PMC5982215 DOI: 10.1039/c7sc05489k] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 04/25/2018] [Indexed: 11/23/2022] Open
Abstract
A natural generalization of the classical deflection function, the functional dependence of the deflection angle on the angular momentum (or the impact parameter), is the joint probability density function of these two quantities, revealing the correlation between them. It provides, at a glance, detailed information about the reaction mechanisms and how changes in the impact parameter affect the product angular distribution. It is also useful to predict the presence of quantum phenomena such as interference. However, the classical angular momentum-scattering angle correlation function has a limited use whenever quantum effects become important. Rigorously speaking, there is not a quantum equivalent of the classical joint distribution, as the differential cross section depends on the coherences between the different values of J caused by the cross terms in the expansion of partial waves. In this article, we present a simple method to calculate a quantum analog of this correlation, a generalized deflection function that can shed light onto the reaction mechanism using just quantum mechanical results. Our results show that there is a very good agreement between the quantum and classical correlation functions as long as quantum effects are not all relevant. When this is not the case, it will also be shown that the quantum correlation function is most useful to observe the extent of quantum effects such as interference among different reaction mechanisms.
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Affiliation(s)
- P G Jambrina
- Departamento de Química Física Aplicada , Universidad Autonoma de Madrid , 28049 , Madrid , Spain .
| | - M Menéndez
- Departamento de Química Física I , Facultad de Ciencias Químicas , Universidad Complutense de Madrid , 28040 Madrid , Spain .
| | - F J Aoiz
- Departamento de Química Física I , Facultad de Ciencias Químicas , Universidad Complutense de Madrid , 28040 Madrid , Spain .
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7
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Lü R. Low-energy stereodynamics in the ion–molecule reactions D+ + D2/HD and H+ + H2/HD: reagent vibrational excitation effect and mass factor effect. Theor Chem Acc 2018. [DOI: 10.1007/s00214-018-2233-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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8
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He H, Zhu W, Su W, Dong L, Li B. Accurate Quantum Wave Packet Study of the Deep Well D + + HD Reaction: Product Ro-vibrational State-Resolved Integral and Differential Cross Sections. J Phys Chem A 2018; 122:2319-2328. [DOI: 10.1021/acs.jpca.7b08941] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Haixiang He
- School of Chemistry & Chemical Engineering, Guangxi University, Nanning 530004, People’s Republic of China
| | - Weimin Zhu
- School of Chemistry & Chemical Engineering, Guangxi University, Nanning 530004, People’s Republic of China
| | - Wenli Su
- School of Chemistry & Chemical Engineering, Guangxi University, Nanning 530004, People’s Republic of China
| | - Lihui Dong
- School of Chemistry & Chemical Engineering, Guangxi University, Nanning 530004, People’s Republic of China
| | - Bin Li
- School of Chemistry & Chemical Engineering, Guangxi University, Nanning 530004, People’s Republic of China
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9
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Esposito F, Coppola CM, De Fazio D. Complementarity between Quantum and Classical Mechanics in Chemical Modeling. The H + HeH+ → H2 + + He Reaction: A Rigourous Test for Reaction Dynamics Methods. J Phys Chem A 2015; 119:12615-26. [PMID: 26583384 DOI: 10.1021/acs.jpca.5b09660] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In this work we present a dynamical study of the H + HeH+ → H2+ + He reaction in a collision energy range from 0.1 meV to 10 eV, suitable to be used in applicative models. The paper extends and complements a recent work [ Phys. Chem. Chem. Phys. 2014, 16, 11662] devoted to the characterization of the reactivity from the ultracold regime up to the three-body dissociation breakup. In particular, the accuracy of the quasi-classical trajectory method below the three-body dissociation threshold has been assessed by a detailed comparison with previous calculations performed with different reaction dynamics methods, whereas the reliability of the results in the high energy range has been checked by a direct comparison with the available experimental data. Integral cross sections for several HeH+ roto-vibrational states have been analyzed and used to understand the extent of quantum effects in the reaction dynamics. By using the quasi-classical trajectory method and quantum mechanical close coupling data, respectively, in the high and low collision energy ranges, we obtain highly accurate thermal rate costants until 15 000 K including all (178) the roto-vibrational bound and quasi-bound states of HeH+. The role of the collision-induced dissociation is also discussed and explicitly calculated for the ground roto-vibrational state of HeH+.
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Affiliation(s)
- Fabrizio Esposito
- Consiglio Nazionale delle Ricerche, Istituto di Nanotecnologia, via Amendola 122/d, 70126 Bari, Italy
| | - Carla Maria Coppola
- Consiglio Nazionale delle Ricerche, Istituto di Nanotecnologia, via Amendola 122/d, 70126 Bari, Italy.,INAF-Osservatorio Astrofisico di Arcetri , 50125 Firenze, Italy
| | - Dario De Fazio
- Consiglio Nazionale delle Ricerche, Istituto di Struttura della Materia, Area della Ricerca di Roma 1, 00016 Roma, Italy
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10
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Larrégaray P, Bonnet L. Quantum state-resolved differential cross sections for complex-forming chemical reactions: Asymmetry is the rule, symmetry the exception. J Chem Phys 2015; 143:144113. [DOI: 10.1063/1.4933009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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11
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Rajagopala Rao T, Mahapatra S, Honvault P. A comparative account of quantum dynamics of the H⁺ + H₂ reaction at low temperature on two different potential energy surfaces. J Chem Phys 2015; 141:064306. [PMID: 25134570 DOI: 10.1063/1.4892043] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Rotationally resolved reaction probabilities, integral cross sections, and rate constant for the H(+) + H2 (v = 0, j = 0 or 1) → H2 (v' = 0, j') + H(+) reaction are calculated using a time-independent quantum mechanical method and the potential energy surface of Kamisaka et al. [J. Chem. Phys. 116, 654 (2002)] (say KBNN PES). All partial wave contributions of the total angular momentum, J, are included to obtain converged cross sections at low collision energies and rate constants at low temperatures. In order to test the accuracy of the KBNN PES, the results obtained here are compared with those obtained in our earlier work [P. Honvault et al., Phys. Rev. Lett. 107, 023201 (2011)] using the accurate potential energy surface of Velilla et al. [J. Chem. Phys. 129, 084307 (2008)]. Integral cross sections and rate constants obtained on the two potential energy surfaces considered here show remarkable differences in terms of magnitude and dependence on collision energy (or temperature) which can be attributed to the differences observed in the topography of the surfaces near to the entrance channel. This clearly shows the inadequacy of the KBNN PES for calculations at low collision energies.
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Affiliation(s)
- T Rajagopala Rao
- Laboratoire ICB, UMR 6303, CNRS-Université de Bourgogne, 21078 Dijon Cedex, France
| | - S Mahapatra
- School of Chemistry, University of Hyderabad, Hyderabad 500 046, India
| | - P Honvault
- Laboratoire ICB, UMR 6303, CNRS-Université de Bourgogne, 21078 Dijon Cedex, France
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12
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13
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Sahoo T, Ghosh S, Adhikari S, Sharma R, Varandas AJC. Coupled 3D Time-Dependent Wave-Packet Approach in Hyperspherical Coordinates: Application to the Adiabatic Singlet-State(11A′) D+ + H2 Reaction. J Phys Chem A 2014; 118:4837-50. [DOI: 10.1021/jp5035739] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Tapas Sahoo
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, 2A & 2B Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, West Bengal, India
| | - Sandip Ghosh
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, 2A & 2B Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, West Bengal, India
| | - Satrajit Adhikari
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, 2A & 2B Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, West Bengal, India
| | - Rahul Sharma
- Departamento
de Química,
and Centro de Química, Universidade de Coimbra, 3004-535 Coimbra, Portugal
| | - António J. C. Varandas
- Departamento
de Química,
and Centro de Química, Universidade de Coimbra, 3004-535 Coimbra, Portugal
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14
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González-Lezana T, Scribano Y, Honvault P. The D(+) + H2 reaction: differential and integral cross sections at low energy and rate constants at low temperature. J Phys Chem A 2014; 118:6416-24. [PMID: 24802076 DOI: 10.1021/jp501446y] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The D(+) + H2 reaction is investigated by means of a time independent quantum mechanical (TIQM) and statistical quantum mechanical (SQM) methods. Differential cross sections and product rotational distributions obtained with these two theoretical approaches for collision energies between 1 meV and 0.1 eV are compared to analyze the dynamics of the process. The agreement observed between the TIQM differential cross sections and the SQM predictions as the energy increases revealed the role played by the complex-forming mechanism. The importance of a good description of the asymptotic regions is also investigated by calculating rate constants for the title reaction at low temperature.
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15
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González-Lezana T, Honvault P, Scribano Y. Dynamics of the D(+) + H2 → HD + H(+) reaction at the low energy regime by means of a statistical quantum method. J Chem Phys 2014; 139:054301. [PMID: 23927256 DOI: 10.1063/1.4816638] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The D(+) +H2(v = 0, j = 0, 1) → HD+H(+) reaction has been investigated at the low energy regime by means of a statistical quantum mechanical (SQM) method. Reaction probabilities and integral cross sections (ICSs) between a collisional energy of 10(-4) eV and 0.1 eV have been calculated and compared with previously reported results of a time independent quantum mechanical (TIQM) approach. The TIQM results exhibit a dense profile with numerous narrow resonances down to Ec ~ 10(-2) eV and for the case of H2(v = 0, j = 0) a prominent peak is found at ~2.5 × 10(-4) eV. The analysis at the state-to-state level reveals that this feature is originated in those processes which yield the formation of rotationally excited HD(v' = 0, j' > 0). The statistical predictions reproduce reasonably well the overall behaviour of the TIQM ICSs at the larger energy range (Ec ≥ 10(-3) eV). Thermal rate constants are in qualitative agreement for the whole range of temperatures investigated in this work, 10-100 K, although the SQM values remain above the TIQM results for both initial H2 rotational states, j = 0 and 1. The enlargement of the asymptotic region for the statistical approach is crucial for a proper description at low energies. In particular, we find that the SQM method leads to rate coefficients in terms of the energy in perfect agreement with previously reported measurements if the maximum distance at which the calculation is performed increases noticeably with respect to the value employed to reproduce the TIQM results.
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16
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Yu S, Su S, Dai D, Yuan K, Yang X. State-to-state dynamics of the H*(n) + HD → D*(n′) + H2 reactive scattering. J Chem Phys 2014; 140:034310. [DOI: 10.1063/1.4861759] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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17
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18
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Jambrina PG, Lara M, Menéndez M, Launay JM, Aoiz FJ. Rate coefficients from quantum and quasi-classical cumulative reaction probabilities for the S(1D) + H2 reaction. J Chem Phys 2013; 137:164314. [PMID: 23126717 DOI: 10.1063/1.4761894] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Cumulative reaction probabilities (CRPs) at various total angular momenta have been calculated for the barrierless reaction S((1)D) + H(2) → SH + H at total energies up to 1.2 eV using three different theoretical approaches: time-independent quantum mechanics (QM), quasiclassical trajectories (QCT), and statistical quasiclassical trajectories (SQCT). The calculations have been carried out on the widely used potential energy surface (PES) by Ho et al. [J. Chem. Phys. 116, 4124 (2002)] as well as on the recent PES developed by Song et al. [J. Phys. Chem. A 113, 9213 (2009)]. The results show that the differences between these two PES are relatively minor and mostly related to the different topologies of the well. In addition, the agreement between the three theoretical methodologies is good, even for the highest total angular momenta and energies. In particular, the good accordance between the CRPs obtained with dynamical methods (QM and QCT) and the statistical model (SQCT) indicates that the reaction can be considered statistical in the whole range of energies in contrast with the findings for other prototypical barrierless reactions. In addition, total CRPs and rate coefficients in the range of 20-1000 K have been calculated using the QCT and SQCT methods and have been found somewhat smaller than the experimental total removal rates of S((1)D).
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Affiliation(s)
- P G Jambrina
- Departamento de Química Física, Facultad de Química, Universidad Complutense, 28040 Madrid, Spain
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19
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Gerlich D, Plašil R, Zymak I, Hejduk M, Jusko P, Mulin D, Glosík J. State specific stabilization of H+ + H2(j) collision complexes. J Phys Chem A 2013; 117:10068-75. [PMID: 23496053 DOI: 10.1021/jp400917v] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Stabilization of H3(+) collision complexes has been studied at nominal temperatures between 11 and 33 K using a 22-pole radio frequency (rf) ion trap. Apparent binary rate coefficients, k(*) = kr + k3[H2], have been measured for para- and normal-hydrogen at number densities between some 10(11) and 10(14) cm(-3). The state specific rate coefficients extracted for radiative stabilization, kr(T;j), are all below 2 × 10(-16) cm(3) s(-1). There is a slight tendency to decrease with increasing temperature. In contrast to simple expectations, kr(11 K;j) is for j = 0 a factor of 2 smaller than for j = 1. The ternary rate coefficients for p-H2 show a rather steep T-dependence; however, they are increasing with temperature. The state specific ternary rate coefficients, k3(T;j), measured for j = 0 and derived for j = 1 from measurements with n-H2, differ by an order of magnitude. Most of these surprising observations are in disagreement with predictions from standard association models, which are based on statistical assumptions and the separation of complex formation and competition between stabilization and decay. Most probably, the unexpected collision dynamics are due to the fact that, at the low translational energies of the present experiment, only a small number of partial waves participate. This should make exact quantum mechanical calculations of kr feasible. More complex is three-body stabilization, because it occurs on the H5(+) potential energy surface.
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Affiliation(s)
- D Gerlich
- Faculty of Mathematics and Physics, Charles University , 121 16 Prague, Czech Republic
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20
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Honvault P, Scribano Y. State-to-state quantum mechanical calculations of rate coefficients for the D+ + H2 → HD + H+ reaction at low temperature. J Phys Chem A 2013; 117:9778-84. [PMID: 23452294 DOI: 10.1021/jp3124549] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The dynamics of the D(+) + H2 → HD + H(+) reaction on a recent ab initio potential energy surface (Velilla, L.; Lepetit, B.; Aguado, A.; Beswick, J. A.; Paniagua, M. J. Chem. Phys. 2008, 129, 084307) has been investigated by means of a time-independent quantum mechanical approach. Cross-sections and rate coefficients are calculated, respectively, for collision energies below 0.1 eV and temperatures up to 100 K for astrophysical application. An excellent accord is found for collision energy above 5 meV, while a disagreement between theory and experiment is observed below this energy. We show that the rate coefficients reveal a slightly temperature-dependent behavior in the upper part of the temperature range considered here. This is in agreement with the experimental data above 80 K, which give a temperature independent value. However, a significant decrease is found at temperatures below 20 K. This decrease can be related to quantum effects and the decay back to the reactant channel, which are not considered by simple statistical approaches, such as the Langevin model. Our results have been fitted to appropriate analytical expressions in order to be used in astrochemical and cosmological models.
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Affiliation(s)
- P Honvault
- Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR CNRS 6303, Université de Bourgogne , 21078 Dijon Cedex, and UFR Sciences et Techniques, Université de Franche-Comté , 25030 Besançon cedex, France
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21
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Plasil R, Zymak I, Jusko P, Mulin D, Gerlich D, Glosík J. Stabilization of H+-H2 collision complexes between 11 and 28 K. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2012; 370:5066-5073. [PMID: 23028154 DOI: 10.1098/rsta.2012.0098] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Formation of H(3)(+) via association of H(+) with H(2) has been studied at low temperatures using a 22-pole radiofrequency trap. Operating at hydrogen number densities from 10(11) to 10(14) cm(-3), the contributions of radiative, k(r), and ternary, k(3), association have been extracted from the measured apparent binary rate coefficients, k*=k(r)+k(3)[H(2)]. Surprisingly, k(3) is constant between 11 and 22 K, (2.6±0.8)×10(-29) cm(6) s(-1), while radiative association decreases from k(r)(11 K)=(1.6±0.3)×10(-16) cm(3) s(-1) to k(r)(28 K)=(5±2)×10(-17) cm(3) s(-1). These results are in conflict with simple association models in which formation and stabilization of the complex are treated separately. Tentative explanations are based on the fact that, at low temperatures, only few partial waves contribute to the formation of the collision complex and that ternary association with H(2) may be quite inefficient because of the 'shared proton' structure of H(5)(+).
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Affiliation(s)
- Radek Plasil
- Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic.
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22
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Xu W, Li W, Lv S, Zhai H, Duan Z, Zhang P. Coriolis Coupling Effects in O+(4S) + H2(X1Σg+) → OH+(X3Σ–) + H(2S) Reaction and Its Isotopic Variants: Exact Time-Dependent Quantum Scattering Study. J Phys Chem A 2012; 116:10882-8. [DOI: 10.1021/jp305612t] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Wenwu Xu
- State Key
Laboratory of Molecular Reaction Dynamics,
Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian 116023, China
| | - Wenliang Li
- State Key
Laboratory of Molecular Reaction Dynamics,
Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian 116023, China
| | - Shuangjiang Lv
- State Key
Laboratory of Molecular Reaction Dynamics,
Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian 116023, China
| | - Hongsheng Zhai
- State Key
Laboratory of Molecular Reaction Dynamics,
Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian 116023, China
| | - Zhixin Duan
- State Key
Laboratory of Molecular Reaction Dynamics,
Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian 116023, China
| | - Peiyu Zhang
- State Key
Laboratory of Molecular Reaction Dynamics,
Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian 116023, China
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23
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Gómez-Carrasco S, González-Sánchez L, Aguado A, Sanz-Sanz C, Zanchet A, Roncero O. Dynamically biased statistical model for the ortho/para conversion in the H2+H3+ → H3++ H2 reaction. J Chem Phys 2012; 137:094303. [DOI: 10.1063/1.4747548] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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