1
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Szűcs T, Czakó G. ManyHF-based full-dimensional potential energy surface development and quasi-classical dynamics for the Cl + CH3NH2 reaction. J Chem Phys 2023; 159:134306. [PMID: 37791624 DOI: 10.1063/5.0166680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 09/06/2023] [Indexed: 10/05/2023] Open
Abstract
A full-dimensional spin-orbit (SO)-corrected potential energy surface (PES) is developed for the Cl + CH3NH2 multi-channel system. Using the new PES, a comprehensive reaction dynamics investigation is performed for the most reactive hydrogen-abstraction reactions forming HCl + CH2NH2/CH3NH. Hartree-Fock (HF) convergence problems in the reactant region are handled by the ManyHF method, which finds the lowest-energy HF solution considering several different initial guess orbitals. The PES development is carried out with the Robosurfer program package, which iteratively improves the surface. Energy points are computed at the ManyHF-UCCSD(T)-F12a/cc-pVDZ-F12 level of theory combined with basis set (ManyHF-RMP2-F12/cc-pVTZ-F12 - ManyHF-RMP2-F12/cc-pVDZ-F12) and SO (MRCI+Q/aug-cc-pwCVDZ) corrections. Quasi-classical trajectory simulations show that the CH3-side hydrogen abstraction occurs more frequently in contrast to the NH2-side reaction. In both cases, the integral cross sections decrease with increasing collision energy (Ecoll). A reaction mechanism shifting from indirect to direct stripping can be observed from the opacity functions, scattering angle, and translation energy distributions as Ecoll increases. Initial attack angle distributions reveal that chlorine prefers to abstract hydrogen from the approached functional group. The collision-energy dependence of the product energy distributions shows that the initial translational energy mainly transfers to product recoil. The HCl vibrational and rotational energy values are comparable and nearly independent of collision energy, while the CH2NH2 and CH3NH co-products' vibrational energy values are higher than the rotational energy values with more significant Ecoll dependence. The HCl(v = 0) rotational distributions are compared with experiment, setting the direction for future investigations.
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Affiliation(s)
- Tímea Szűcs
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary
| | - Gábor Czakó
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary
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2
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Reaction pathways for palladium(I) reduction in laser-induced particle formation of Pd: An ab initio molecular orbital study. Chem Phys 2023. [DOI: 10.1016/j.chemphys.2023.111857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
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3
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Ab initio characterization of the potential energy profiles for the multi-channel reactions: H/Cl + CH3OH. COMPUT THEOR CHEM 2022. [DOI: 10.1016/j.comptc.2022.113906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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4
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Papp D, Czakó G. Vibrational mode-specific dynamics of the F( 2P 3/2) + C 2H 6 → HF + C 2H 5 reaction. J Chem Phys 2021; 155:154302. [PMID: 34686045 DOI: 10.1063/5.0069658] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We investigate the competing effect of vibrational and translational excitation and the validity of the Polanyi rules in the early- and negative-barrier F(2P3/2) + C2H6 → HF + C2H5 reaction by performing quasi-classical dynamics simulations on a recently developed full-dimensional multi-reference analytical potential energy surface. The effect of five normal-mode excitations of ethane on the reactivity, the mechanism, and the post-reaction energy flow is followed through a wide range of collision energies. Promoting effects of vibrational excitations and interaction time, related to the slightly submerged barrier, are found to be suppressed by the early-barrier-induced translational enhancement, in contrast to the slightly late-barrier Cl + C2H6 reaction. The excess vibrational energy mostly converts into ethyl internal excitation while collision energy is transformed into product separation. The substantial reaction energy excites the HF vibration, which tends to show mode-specificity and translational energy dependence as well. With increasing collision energy, direct stripping becomes dominant over the direct rebound and indirect mechanisms, being basically independent of reactant excitation.
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Affiliation(s)
- Dóra Papp
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary
| | - Gábor Czakó
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary
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5
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Papp D, Li J, Guo H, Czakó G. Vibrational mode-specificity in the dynamics of the Cl + C 2H 6 → HCl + C 2H 5 reaction. J Chem Phys 2021; 155:114303. [PMID: 34551541 DOI: 10.1063/5.0062677] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
We report a detailed dynamics study on the mode-specificity of the Cl + C2H6 → HCl + C2H5 H-abstraction reaction. We perform quasi-classical trajectory simulations using a recently developed high-level ab initio full-dimensional potential energy surface by exciting five different vibrational modes of ethane at four collision energies. We find that all the studied vibrational excitations, except that of the CC-stretching mode, clearly promote the title reaction, and the vibrational enhancements are consistent with the predictions of the Sudden Vector Projection (SVP) model, with the largest effect caused by the CH-stretching excitations. Intramolecular vibrational redistribution is also monitored for the differently excited ethane molecule. Our results indicate that the mechanism of the reaction changes with increasing collision energy, with no mode-specificity at high energies. The initial translational energy mostly converts into product recoil, while a significant part of the excess vibrational energy remains in the ethyl radical. An interesting competition between translational and vibrational energies is observed for the HCl vibrational distribution: the effect of exciting the low-frequency ethane modes, having small SVP values, is suppressed by translational excitation, whereas a part of the excess vibrational energy pumped into the CH-stretching modes (larger SVP values) efficiently flows into the HCl vibration.
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Affiliation(s)
- Dóra Papp
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary
| | - Jun Li
- School of Chemistry and Chemical Engineering and Chongqing Key Laboratory of Theoretical and Computational Chemistry, Chongqing University, Chongqing 401331, China
| | - Hua Guo
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - Gábor Czakó
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary
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6
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Sharipov AS, Loukhovitski BI. Energy disposal into the vibrational degrees of freedom of bimolecular reaction products: Key factors and simple model. Chem Phys 2021. [DOI: 10.1016/j.chemphys.2021.111098] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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7
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Papp D, Tajti V, Győri T, Czakó G. Theory Finally Agrees with Experiment for the Dynamics of the Cl + C 2H 6 Reaction. J Phys Chem Lett 2020; 11:4762-4767. [PMID: 32441943 PMCID: PMC7309313 DOI: 10.1021/acs.jpclett.0c01263] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Accepted: 05/22/2020] [Indexed: 05/07/2023]
Abstract
Since the pioneering reaction dynamics studies of H + H2 in the 1970s, theory increased the system size by one atom in every decade arriving to six-atom reactions in the early 2010s. Here, we take a significant step forward by reporting accurate dynamics simulations for the nine-atom Cl + ethane (C2H6) reaction using a new high-quality spin-orbit-ground-state ab initio potential energy surface. Quasi-classical trajectory simulations on this surface cool the rotational distribution of the HCl product molecules, thereby providing unprecedented agreement with experiment after several previous failed attempts of theory. Unlike Cl + CH4, the Cl + C2H6 reaction is exothermic with an adiabatically submerged transition state, allowing testing of the validity of the Polanyi rules for a negative-barrier reaction.
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Affiliation(s)
- Dóra Papp
- MTA-SZTE Lendület Computational
Reaction Dynamics Research Group, Interdisciplinary Excellence Centre
and Department of Physical Chemistry and Materials Science, Institute
of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary
| | - Viktor Tajti
- MTA-SZTE Lendület Computational
Reaction Dynamics Research Group, Interdisciplinary Excellence Centre
and Department of Physical Chemistry and Materials Science, Institute
of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary
| | - Tibor Győri
- MTA-SZTE Lendület Computational
Reaction Dynamics Research Group, Interdisciplinary Excellence Centre
and Department of Physical Chemistry and Materials Science, Institute
of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary
| | - Gábor Czakó
- MTA-SZTE Lendület Computational
Reaction Dynamics Research Group, Interdisciplinary Excellence Centre
and Department of Physical Chemistry and Materials Science, Institute
of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary
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8
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QCT study of the vibrational and translational role in the H + C2H6(ν1, ν2, ν5, ν7, ν9 and ν10) reactions. Theor Chem Acc 2019. [DOI: 10.1007/s00214-019-2504-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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9
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Blackshaw KJ, Ortega BI, Quartey NK, Fritzeen WE, Korb RT, Ajmani AK, Montgomery L, Marracci M, Vanegas GG, Galvan J, Sarvas Z, Petit AS, Kidwell NM. Nonstatistical Dissociation Dynamics of Nitroaromatic Chromophores. J Phys Chem A 2019; 123:4262-4273. [DOI: 10.1021/acs.jpca.9b02312] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- K. Jacob Blackshaw
- Department of Chemistry, The College of William and Mary, Williamsburg, Virginia 23187-8795, United States
| | - Belinda I. Ortega
- Department of Chemistry and Biochemistry, California State University—Fullerton, Fullerton, California 92834-6866, United States
| | - Naa-Kwarley Quartey
- Department of Chemistry, The College of William and Mary, Williamsburg, Virginia 23187-8795, United States
| | - Wade E. Fritzeen
- Department of Chemistry, The College of William and Mary, Williamsburg, Virginia 23187-8795, United States
| | - Robert T. Korb
- Department of Chemistry, The College of William and Mary, Williamsburg, Virginia 23187-8795, United States
| | - Annalise K. Ajmani
- Department of Chemistry, The College of William and Mary, Williamsburg, Virginia 23187-8795, United States
| | - Lehman Montgomery
- Department of Chemistry, The College of William and Mary, Williamsburg, Virginia 23187-8795, United States
| | - Marcus Marracci
- Department of Chemistry and Biochemistry, California State University—Fullerton, Fullerton, California 92834-6866, United States
| | - Geronimo Gudino Vanegas
- Department of Chemistry and Biochemistry, California State University—Fullerton, Fullerton, California 92834-6866, United States
| | - John Galvan
- Department of Chemistry and Biochemistry, California State University—Fullerton, Fullerton, California 92834-6866, United States
| | - Zach Sarvas
- Department of Chemistry and Biochemistry, California State University—Fullerton, Fullerton, California 92834-6866, United States
| | - Andrew S. Petit
- Department of Chemistry and Biochemistry, California State University—Fullerton, Fullerton, California 92834-6866, United States
| | - Nathanael M. Kidwell
- Department of Chemistry, The College of William and Mary, Williamsburg, Virginia 23187-8795, United States
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10
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Papp D, Gruber B, Czakó G. Detailed benchmark ab initio mapping of the potential energy surfaces of the X + C2H6 [X = F, Cl, Br, I] reactions. Phys Chem Chem Phys 2019; 21:396-408. [DOI: 10.1039/c8cp06445h] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We provide benchmark relative energies for the stationary points of three different channels of the halogen atom + ethane reactions.
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Affiliation(s)
- Dóra Papp
- Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science
- Institute of Chemistry
- University of Szeged
- Szeged H-6720
- Hungary
| | - Balázs Gruber
- Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science
- Institute of Chemistry
- University of Szeged
- Szeged H-6720
- Hungary
| | - Gábor Czakó
- Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science
- Institute of Chemistry
- University of Szeged
- Szeged H-6720
- Hungary
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11
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Espinosa-Garcia J, Martinez-Nuñez E, Rangel C. Quasi-Classical Trajectory Dynamics Study of the Cl( 2P) + C 2H 6 → HCl(v,j) + C 2H 5 Reaction. Comparison with Experiment. J Phys Chem A 2018; 122:2626-2633. [PMID: 29489365 DOI: 10.1021/acs.jpca.8b00149] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
To understand and simulate the dynamics behavior of the title reaction, QCT calculations were performed on a recently developed global analytical potential energy surface, PES-2017. These calculations combine the classical description of the dynamics with pseudoquantization in the reactants and products to perform a theoretical/experimental comparison on the same footing. Thus, in the products a series of constraints are included to analyze the HCl(v = 0,j) product, which is experimentally detected. At collision energies of 5.5 and 6.7 kcal mol-1 the largest fraction of available energy is deposited as translation, 67%, while the ethyl radical shows significant internal energy, 27%, and so it does not act as a spectator of the reaction, thus reproducing recent experimental evidence. The HCl(v=0, j) rotational distribution is cold, peaking at j = 2, only one unit hotter than experiment, which represents an error of 0.12 kcal mol-1. At a collision energy of 5.5 kcal mol-1 product translational distribution is slightly hotter than experiment, but at 6.7 kcal mol-1 agreement with recent experiments is practically quantitative, suggesting that the first experiments should be revised. In addition, we observe that the HCl(v=0, j) scattering distribution shifts from isotropic at low values of j to backward at high values of j, which is in agreement with experimental data. Finally, no evidence was found for the "chattering" mechanism suggested to explain the low translational energy of the HCl product in the backward scattering region. In sum, agreement with experiments of a series of sensible dynamic properties permits us to be optimistic on the quality and accuracy of the theoretical tools used in the present work, QCT and PES-2017.
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Affiliation(s)
- Joaquin Espinosa-Garcia
- Departamento de Química Física and Instituto de Computacion Cientifica Avanzada , Universidad de Extremadura , 06071 Badajoz , Spain
| | - Emilio Martinez-Nuñez
- Departamento de Química Física , Universidad de Santiago de Compostela , Santiago de Compostela , Spain
| | - Cipriano Rangel
- Departamento de Química Física and Instituto de Computacion Cientifica Avanzada , Universidad de Extremadura , 06071 Badajoz , Spain
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12
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Abstract
The dynamics of chemical reactions in liquid solutions are now amenable to direct study using ultrafast laser spectroscopy techniques and advances in computer simulation methods. The surrounding solvent affects the chemical reaction dynamics in numerous ways, which include: (i) formation of complexes between reactants and solvent molecules; (ii) modifications to transition state energies and structures relative to the reactants and products; (iii) coupling between the motions of the reacting molecules and the solvent modes, and exchange of energy; (iv) solvent caging of reactants and products; and (v) structural changes to the solvation shells in response to the changing chemical identity of the solutes, on timescales which may be slower than the reactive events. This article reviews progress in the study of bimolecular chemical reaction dynamics in solution, concentrating on reactions which occur on ground electronic states. It illustrates this progress with reference to recent experimental and computational studies, and considers how the various ways in which a solvent affects the chemical reaction dynamics can be unravelled. Implications are considered for research in fields such as mechanistic synthetic chemistry.
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Affiliation(s)
- Andrew J Orr-Ewing
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.
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13
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Pandit S, Hornung B, Dunning GT, Preston TJ, Brazener K, Orr-Ewing AJ. Primary vs. secondary H-atom abstraction in the Cl-atom reaction with n-pentane. Phys Chem Chem Phys 2018; 19:1614-1626. [PMID: 27995254 DOI: 10.1039/c6cp07164c] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Velocity map imaging (VMI) measurements and quasi-classical trajectory (QCT) calculations on a newly developed, global potential energy surface (PES) combine to reveal the detailed mechanisms of reaction of Cl atoms with n-pentane. Images of the HCl (v = 0, J = 1, 2 and 3) products of reaction at a mean collision energy of 33.5 kJ mol-1 determine the centre-of-mass frame angular scattering and kinetic energy release distributions. The HCl products form with relative populations of J = 0-5 levels that fit to a rotational temperature of 138 ± 13 K. Product kinetic energy release distributions agree well with those derived from a previous VMI study of the pentyl radical co-product [Estillore et al., J. Chem. Phys. 2010, 132, 164313], but the angular distributions show more pronounced forward scattering. The QCT calculations reproduce many of the experimental observations, and allow comparison of the site-specific dynamics of abstraction of primary and secondary H-atoms. They also quantify the relative reactivity towards Cl atoms of the three different H-atom environments in n-pentane.
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Affiliation(s)
- Shubhrangshu Pandit
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.
| | - Balázs Hornung
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.
| | - Greg T Dunning
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.
| | - Thomas J Preston
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.
| | - Kristian Brazener
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.
| | - Andrew J Orr-Ewing
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.
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14
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Rangel C, Espinosa-Garcia J. Full-dimensional analytical potential energy surface describing the gas-phase Cl + C2H6 reaction and kinetics study of rate constants and kinetic isotope effects. Phys Chem Chem Phys 2018; 20:3925-3938. [DOI: 10.1039/c7cp07592h] [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
Within the Born–Oppenheimer approximation a full-dimensional analytical potential energy surface, PES-2017, was developed for the gas-phase hydrogen abstraction reaction between the chlorine atom and ethane, which is a nine body system.
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Affiliation(s)
- Cipriano Rangel
- Departamento de Química Física and Instituto de Computación Científica Avanzada
- Universidad de Extremadura
- 06071 Badajoz
- Spain
| | - Joaquin Espinosa-Garcia
- Departamento de Química Física and Instituto de Computación Científica Avanzada
- Universidad de Extremadura
- 06071 Badajoz
- Spain
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15
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Pandit S, Hornung B, Orr-Ewing AJ. Direct comparison of 3-centre and 4-centre HBr elimination pathways in methyl-substituted vinyl bromides. Phys Chem Chem Phys 2016; 18:28353-28364. [DOI: 10.1039/c6cp05393a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
HBr elimination from energized methyl vinyl bromide molecules can occur through competing 3- and 4-centre transition states.
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16
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Hornung B, Harvey JN, Preston TJ, Dunning GT, Orr-Ewing AJ. Empirical Valence Bond Theory Studies of the CH4 + Cl → CH3 + HCl Reaction. J Phys Chem A 2015; 119:9590-8. [DOI: 10.1021/acs.jpca.5b06418] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Balázs Hornung
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol, BS8 1TS, United Kingdom
| | - Jeremy N. Harvey
- Department
of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001, Leuven (Heverlee), Belgium
| | - Thomas J. Preston
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol, BS8 1TS, United Kingdom
| | - Greg T. Dunning
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol, BS8 1TS, United Kingdom
| | - Andrew J. Orr-Ewing
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol, BS8 1TS, United Kingdom
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17
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Affiliation(s)
- Andrew J. Orr-Ewing
- School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom;
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18
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Gerber RB, Shemesh D, Varner ME, Kalinowski J, Hirshberg B. Ab initio and semi-empirical Molecular Dynamics simulations of chemical reactions in isolated molecules and in clusters. Phys Chem Chem Phys 2014; 16:9760-75. [DOI: 10.1039/c3cp55239j] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Recent progress in “on-the-fly” trajectory simulations of molecular reactions, using different electronic structure methods is discussed, with analysis of the insights that such calculations can provide and of the strengths and limitations of the algorithms available.
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Affiliation(s)
- R. B. Gerber
- Institute of Chemistry and The Fritz Haber Research Center
- The Hebrew University of Jerusalem
- Jerusalem 91904, Israel
- Department of Chemistry
- University of California
| | - D. Shemesh
- Institute of Chemistry and The Fritz Haber Research Center
- The Hebrew University of Jerusalem
- Jerusalem 91904, Israel
| | - M. E. Varner
- Department of Chemistry
- University of California
- Irvine 92697, USA
| | - J. Kalinowski
- Department of Chemistry
- University of Helsinki
- , Finland
| | - B. Hirshberg
- Institute of Chemistry and The Fritz Haber Research Center
- The Hebrew University of Jerusalem
- Jerusalem 91904, Israel
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19
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Affiliation(s)
- Eric W. McFarland
- Department
of Chemical Engineering, and ‡Department of Chemistry and Biochemistry, University of California, Santa Barbara,
California 93106, United States
| | - Horia Metiu
- Department
of Chemical Engineering, and ‡Department of Chemistry and Biochemistry, University of California, Santa Barbara,
California 93106, United States
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20
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Abou-Chahine F, Greaves SJ, Dunning GT, Orr-Ewing AJ, Greetham GM, Clark IP, Towrie M. Vibrationally resolved dynamics of the reaction of Cl atoms with 2,3-dimethylbut-2-ene in chlorinated solvents. Chem Sci 2013. [DOI: 10.1039/c2sc21267f] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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21
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Zhang B, Liu K, Czakó G, Bowman JM. Translational energy dependence of the Cl + CH4(vb = 0, 1) reactions: a joint crossed-beam and quasiclassical trajectory study. Mol Phys 2012. [DOI: 10.1080/00268976.2012.662600] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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22
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Wodraszka R, Palma J, Manthe U. Vibrational Dynamics of the CH4·F–Complex. J Phys Chem A 2012; 116:11249-59. [DOI: 10.1021/jp3052642] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Robert Wodraszka
- Theoretische Chemie, Fakultät
für Chemie, Universität Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany
| | - Juliana Palma
- Theoretische Chemie, Fakultät
für Chemie, Universität Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany
| | - Uwe Manthe
- Theoretische Chemie, Fakultät
für Chemie, Universität Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany
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23
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Czakó G, Bowman JM. Accurate ab initio potential energy surface, thermochemistry, and dynamics of the Cl(2P, 2P3/2) + CH4 → HCl + CH3 and H + CH3Cl reactions. J Chem Phys 2012; 136:044307. [DOI: 10.1063/1.3679014] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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24
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Estillore AD, Visger-Kiefer LM, Suits AG. Reaction dynamics of Cl + butanol isomers by crossed-beam sliced ion imaging. Faraday Discuss 2012; 157:181-91; discussion 243-84. [DOI: 10.1039/c2fd20059g] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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25
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Pearce JK, Murray C, Stevens PN, Orr-Ewing AJ. H-atom abstraction dynamics of reactions between Cl atoms and heterocyclic organic molecules. Mol Phys 2011. [DOI: 10.1080/00268970500058228] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- J. K. Pearce
- a School of Chemistry , University of Bristol , Cantock's Close, Bristol , BS8 1TS , UK
| | - C. Murray
- a School of Chemistry , University of Bristol , Cantock's Close, Bristol , BS8 1TS , UK
| | - P. N. Stevens
- a School of Chemistry , University of Bristol , Cantock's Close, Bristol , BS8 1TS , UK
| | - A. J. Orr-Ewing
- a School of Chemistry , University of Bristol , Cantock's Close, Bristol , BS8 1TS , UK
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26
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Greaves SJ, Rose RA, Abou-Chahine F, Glowacki DR, Troya D, Orr-Ewing AJ. Quasi-classical trajectory study of the dynamics of the Cl + CH4→ HCl + CH3 reaction. Phys Chem Chem Phys 2011; 13:11438-45. [DOI: 10.1039/c0cp02694h] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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27
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Rose RA, Greaves SJ, Orr-Ewing AJ. Velocity map imaging the dynamics of the reactions of Cl atoms with neopentane and tetramethylsilane. J Chem Phys 2010; 132:244312. [DOI: 10.1063/1.3447378] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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28
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Greaves SJ, Rose RA, Orr-Ewing AJ. Velocity map imaging of the dynamics of bimolecular chemical reactions. Phys Chem Chem Phys 2010; 12:9129-43. [PMID: 20448868 DOI: 10.1039/c001233e] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The experimental technique of velocity map imaging (VMI) enables measurements to be made of the dynamics of chemical reactions that are providing unprecedented insights about reactive scattering. This perspective article illustrates how VMI, in combination with crossed-molecular beam, dual-beam or photo-initiated (Photoloc) methods, can reveal correlated information on the vibrational quantum states populated in the two products of a reaction, and the angular scattering of products (the differential cross section) formed in specific rotational and vibrational levels. Reactions studied by VMI techniques are being extended to those of polyatomic molecules or radicals, and of molecular ions. Subtle quantum-mechanical effects in bimolecular reactions can provide distinct signatures in the velocity map images, and are exemplified here by non-adiabatic dynamics on coupled potential energy surfaces, and by experimental evidence for scattering resonances.
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Affiliation(s)
- Stuart J Greaves
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK
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29
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Miller Y, Finlayson-Pitts BJ, Gerber RB. Ionization of N2O4in Contact with Water: Mechanism, Time Scales and Atmospheric Implications. J Am Chem Soc 2009; 131:12180-5. [DOI: 10.1021/ja900350g] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Yifat Miller
- Department of Physical Chemistry, and The Fritz Haber Research Center, Hebrew University, Jerusalem 91904, Israel, and Department of Chemistry, University of California, Irvine, California 92697-2025
| | - Barbara J. Finlayson-Pitts
- Department of Physical Chemistry, and The Fritz Haber Research Center, Hebrew University, Jerusalem 91904, Israel, and Department of Chemistry, University of California, Irvine, California 92697-2025
| | - R. Benny Gerber
- Department of Physical Chemistry, and The Fritz Haber Research Center, Hebrew University, Jerusalem 91904, Israel, and Department of Chemistry, University of California, Irvine, California 92697-2025
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30
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Tian X, Gao T, He N, Zhang Z. Directab initiomolecular dynamics study of F atom reaction with methane. Mol Phys 2008. [DOI: 10.1080/00268970802665605] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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31
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Zolot AM, Dagdigian PJ, Nesbitt DJ. Quantum-state resolved reactive scattering at the gas-liquid interface: F+squalane (C30H62) dynamics via high-resolution infrared absorption of nascent HF(v,J). J Chem Phys 2008; 129:194705. [DOI: 10.1063/1.2973630] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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32
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Zolot AM, Nesbitt DJ. Crossed jet reactive scattering dynamics of F+H2O→HF(v,J)+OH:HF(v,J) product quantum state distributions under single-collision conditions. J Chem Phys 2008; 129:184305. [DOI: 10.1063/1.2998524] [Citation(s) in RCA: 35] [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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33
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Feilberg KL, Gruber-Stadler M, Johnson MS, Mühlhäuser M, Nielsen CJ. 13C, 18O, and D Fractionation Effects in the Reactions of CH3OH Isotopologues with Cl and OH Radicals. J Phys Chem A 2008; 112:11099-114. [DOI: 10.1021/jp805643x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Karen L. Feilberg
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen OE, Denmark, Centre for Theoretical and Computational Chemistry, Department of Chemistry, University of Oslo, Pb. 1033 - Blindern, N-0315 Oslo, Norway, and Studiengang Umwelt-, Verfahrens- & Biotechnik, MCI - Management Center Innsbruck Internationale Fachhochschulgesellschaft mbH, Egger-Lienz-Straβe 120, A-6020 Innsbruck, Austria
| | - Margret Gruber-Stadler
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen OE, Denmark, Centre for Theoretical and Computational Chemistry, Department of Chemistry, University of Oslo, Pb. 1033 - Blindern, N-0315 Oslo, Norway, and Studiengang Umwelt-, Verfahrens- & Biotechnik, MCI - Management Center Innsbruck Internationale Fachhochschulgesellschaft mbH, Egger-Lienz-Straβe 120, A-6020 Innsbruck, Austria
| | - Matthew S. Johnson
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen OE, Denmark, Centre for Theoretical and Computational Chemistry, Department of Chemistry, University of Oslo, Pb. 1033 - Blindern, N-0315 Oslo, Norway, and Studiengang Umwelt-, Verfahrens- & Biotechnik, MCI - Management Center Innsbruck Internationale Fachhochschulgesellschaft mbH, Egger-Lienz-Straβe 120, A-6020 Innsbruck, Austria
| | - Max Mühlhäuser
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen OE, Denmark, Centre for Theoretical and Computational Chemistry, Department of Chemistry, University of Oslo, Pb. 1033 - Blindern, N-0315 Oslo, Norway, and Studiengang Umwelt-, Verfahrens- & Biotechnik, MCI - Management Center Innsbruck Internationale Fachhochschulgesellschaft mbH, Egger-Lienz-Straβe 120, A-6020 Innsbruck, Austria
| | - Claus J. Nielsen
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen OE, Denmark, Centre for Theoretical and Computational Chemistry, Department of Chemistry, University of Oslo, Pb. 1033 - Blindern, N-0315 Oslo, Norway, and Studiengang Umwelt-, Verfahrens- & Biotechnik, MCI - Management Center Innsbruck Internationale Fachhochschulgesellschaft mbH, Egger-Lienz-Straβe 120, A-6020 Innsbruck, Austria
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34
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Eskola AJ, Timonen RS, Marshall P, Chesnokov EN, Krasnoperov LN. Rate Constants and Hydrogen Isotope Substitution Effects in the CH3 + HCl and CH3 + Cl2 Reactions. J Phys Chem A 2008; 112:7391-401. [DOI: 10.1021/jp801999w] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Arkke J. Eskola
- Laboratory of Physical Chemistry, P.O. Box 55, FIN-00014 University of Helsinki, Finland, Department of Chemistry, University of North Texas, P.O., Box 305070, Denton, Texas 76203-5070, Institute of Chemical Kinetics and Combustion, Institutskaya 3, Novosibirsk, 630090, Russia, and Department of Chemistry and Environmental Science, New Jersey Institute of Technology, Newark, New Jersey 07102
| | - Raimo S. Timonen
- Laboratory of Physical Chemistry, P.O. Box 55, FIN-00014 University of Helsinki, Finland, Department of Chemistry, University of North Texas, P.O., Box 305070, Denton, Texas 76203-5070, Institute of Chemical Kinetics and Combustion, Institutskaya 3, Novosibirsk, 630090, Russia, and Department of Chemistry and Environmental Science, New Jersey Institute of Technology, Newark, New Jersey 07102
| | - Paul Marshall
- Laboratory of Physical Chemistry, P.O. Box 55, FIN-00014 University of Helsinki, Finland, Department of Chemistry, University of North Texas, P.O., Box 305070, Denton, Texas 76203-5070, Institute of Chemical Kinetics and Combustion, Institutskaya 3, Novosibirsk, 630090, Russia, and Department of Chemistry and Environmental Science, New Jersey Institute of Technology, Newark, New Jersey 07102
| | - Evgeni N. Chesnokov
- Laboratory of Physical Chemistry, P.O. Box 55, FIN-00014 University of Helsinki, Finland, Department of Chemistry, University of North Texas, P.O., Box 305070, Denton, Texas 76203-5070, Institute of Chemical Kinetics and Combustion, Institutskaya 3, Novosibirsk, 630090, Russia, and Department of Chemistry and Environmental Science, New Jersey Institute of Technology, Newark, New Jersey 07102
| | - Lev N. Krasnoperov
- Laboratory of Physical Chemistry, P.O. Box 55, FIN-00014 University of Helsinki, Finland, Department of Chemistry, University of North Texas, P.O., Box 305070, Denton, Texas 76203-5070, Institute of Chemical Kinetics and Combustion, Institutskaya 3, Novosibirsk, 630090, Russia, and Department of Chemistry and Environmental Science, New Jersey Institute of Technology, Newark, New Jersey 07102
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35
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Greaves SJ, Orr-Ewing AJ, Troya D. Classical Trajectory Study of the Dynamics of the Reaction of Cl Atoms with Ethane. J Phys Chem A 2008; 112:9387-95. [DOI: 10.1021/jp802347v] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
| | | | - Diego Troya
- Department of Chemistry, Virginia Tech, 107 Davidson Hall, Blacksburg, Virginia, 24061-0212
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36
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Miller Y, Gerber RB. Dynamics of proton recombination with NO3- anion in water clusters. Phys Chem Chem Phys 2008; 10:1091-3. [PMID: 18270608 DOI: 10.1039/b717338p] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Recombination events of a proton with NO3- at (H2O)8 clusters are studied by molecular dynamics, using "on-the-fly" reliable ab initio MP2 potentials. The main findings are: (1) the lifetime of the ions is less than 1.2 picoseconds; (2) the recombination step invariably involves H3O+, not H5O2+; and (3) an essentially unique transition-state structure of H3O+/NO3- for recombination is found in all cases. Proton migration involves both H3O+ and H5O2+ species: Grotthuss and other mechanisms contribute.
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Affiliation(s)
- Yifat Miller
- Department of Physical Chemistry and the Fritz Haber Research Center for Molecular Dynamics, Hebrew University, Jerusalem, 91904, Israel
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37
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Retail B, Rose RA, Pearce JK, Greaves SJ, Orr-Ewing AJ. The dynamics of reaction of Cl atoms with tetramethylsilane. Phys Chem Chem Phys 2008; 10:1675-80. [DOI: 10.1039/b716512a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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38
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Nyman G, Zhou J, Zhang B, Liu K. Crossed-Beam and Quantum Dynamics Studies of the Reaction Cl + CHD3. Isr J Chem 2007. [DOI: 10.1560/ijc.47.1.1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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39
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Pearce JK, Retail B, Greaves SJ, Rose RA, Orr-Ewing AJ. Imaging the Dynamics of Reactions between Cl Atoms and the Cyclic Ethers Oxirane and Oxetane. J Phys Chem A 2007; 111:13296-304. [DOI: 10.1021/jp0773684] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Julie K. Pearce
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, United Kingdom
| | - Bertrand Retail
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, United Kingdom
| | - Stuart J. Greaves
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, United Kingdom
| | - Rebecca A. Rose
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, United Kingdom
| | - Andrew J. Orr-Ewing
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, United Kingdom
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40
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Zolot AM, Nesbitt DJ. Quantum state resolved scattering dynamics of F+HCl→HF(v,J)+Cl. J Chem Phys 2007; 127:114319. [PMID: 17887849 DOI: 10.1063/1.2770464] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
State-to-state reaction dynamics of the reaction F+HCl-->HF(v,J)+Cl have been studied under single-collision conditions using an intense discharge F atom source in crossed supersonic molecular beams at Ecom=4.3(1.3) kcal/mol. Nascent HF product is monitored by shot-noise limited direct infrared laser absorption, providing quantum state distributions as well as additional information on kinetic energy release from high resolution Dopplerimetry. The vibrational distributions are highly inverted, with 34(4)%, 44(2)%, and 8(1)% of the total population in vHF=1, 2, and 3, respectively, consistent with predominant energy release into the newly formed bond. However, there is a small [14(1)%] but significant formation channel into the vHF=0 ground state, which is directly detectable for the first time via direct absorption methods. Of particular dynamical interest, both the HF(v=2,J) and HF(v=1,J) populations exhibit strongly bimodal J distributions. These results differ significantly from previous flow and arrested-relaxation studies and may signal the presence of microscopic branching in the reaction dynamics.
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Affiliation(s)
- A M Zolot
- JILA, National Institute of Standards and Technology and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
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41
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Greaves SJ, Kim J, Orr-Ewing AJ, Troya D. Studying ‘chattering collisions’ in the Cl+ethane reaction with classical trajectories. Chem Phys Lett 2007. [DOI: 10.1016/j.cplett.2007.05.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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42
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Retail B, Greaves SJ, Pearce JK, Rose RA, Orr-Ewing AJ. Imaging the nonadiabatic dynamics of the CH3 + HCl reaction. Phys Chem Chem Phys 2007; 9:3261-7. [PMID: 17579734 DOI: 10.1039/b704463a] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
LAB-frame velocity distributions of Cl-atoms produced in the photoinitiated reaction of CH(3) radicals with HCl have been measured for both the ground Cl ((2)P(3/2)) and excited Cl* ((2)P(1/2)) spin-orbit states using a DC slice velocity-map ion imaging technique. The similarity of these distributions, as well as the average internal excitation of methane co-products for both Cl and Cl* pathways, suggest that all the reactive flux proceeds through the same transition state on the ground potential energy surface (PES) and that the couplings which promote nonadiabatic transitions to the excited PES correlating to Cl* occur later in the exit channel, beyond the TS region. The nature of these couplings is discussed in light of initial vibrational excitation of CH(3) radicals as well as previously reported nonadiabatic reactivity in other polyatomic molecule reactions. Furthermore, the scattering of the reaction products, derived using the photoloc method, suggests that at the high collision energy of our experiment (E(coll) = 22.3 kcal mol(-1)), large impact parameter collisions are favoured with a reduced kinematic constraint on the internal excitation of the methane co-product.
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Affiliation(s)
- Bertrand Retail
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, UKBS8 1TS
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43
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Banks ST, Clary DC. Reduced dimensionality quantum dynamics of Cl + CH4? HCl + CH3 on an ab initio potential. Phys Chem Chem Phys 2007; 9:933-43. [PMID: 17301883 DOI: 10.1039/b615460c] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We study the reaction Cl + CH(4)--> HCl + CH(3) using a 2-D potential energy surface obtained by fitting a double Morse analytical function to high level (CCSD(T)/cc-pVTZ//MP2/cc-pVTZ)ab initio data. Dynamics simulations are performed in hyperspherical coordinates with the close-coupled equations being solved using R-matrix propagation. Quantum contributions from spectator modes are included via a harmonic zero-point correction to the ab initio data prior to fitting the potential. This is the first time this method has been applied to a heavy-light-heavy reaction and the first time it has been used to study differential cross sections. We find thermal rate constants and state-to-state differential cross sections which are in good agreement with experimental data. We discuss the applicability of our method to the study of kinetic isotope effects (KIEs), which we derive for the CH(4)/CD(4) substitution. The calculated KIE compares favourably with experiment. Finally, we discuss the sensitivity of the results of dynamics simulations on the accuracy of the fitted potential.
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Affiliation(s)
- Simon T Banks
- Physical and Theoretical Chemistry Department, University of Oxford, South Parks Road, Oxford, UK.
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44
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Huang C, Li W, Suits AG. Rotationally resolved reactive scattering: Imaging detailed Cl+C2H6 reaction dynamics. J Chem Phys 2006; 125:133107. [PMID: 17029433 DOI: 10.1063/1.2202827] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The hydrogen atom abstraction reaction of Cl (2P3/2) with ethane has been studied using the crossed molecular beam technique with dc slice imaging at collision energies from 3.2 to 10.4 kcal/mol. The products HCl (v,J) (v = 0, J = 0-5) were state-selectively detected using 2+1 resonance enhanced multiphoton ionization. The images were used to obtain the center-of-mass frame product angular distributions and translational energy release distributions. Two general features were found in all probed HCl quantum states at 6.7 kcal/mol collision energy, and these features have distinct translational energy release and angular distributions, as described for HCl (v = 0, J = 2) in a recent preliminary report [Li et al., J. Chem. Phys. 124, 011102 (2006)]. The results for HCl (v = 0, J = 2) at four collision energies were also compared to investigate the energy-dependent dynamics. We discuss the reaction in terms of a variety of models of polyatomic reaction dynamics. The dynamics of this well studied system are more complicated than can be accounted for by a single mechanism, and the results call for further theoretical and experimental investigations.
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Affiliation(s)
- Cunshun Huang
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, USA
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45
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Castillo JF, Aoiz FJ, Bañares L. Quasiclassical trajectory study of the Cl+CH4 reaction dynamics on a quadratic configuration interaction with single and double excitation interpolated potential energy surface. J Chem Phys 2006; 125:124316. [PMID: 17014183 DOI: 10.1063/1.2357741] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
An ab initio interpolated potential energy surface (PES) for the Cl+CH(4) reactive system has been constructed using the interpolation method of Collins and co-workers [J. Chem. Phys. 102, 5647 (1995); 108, 8302 (1998); 111, 816 (1999); Theor. Chem. Acc. 108, 313 (2002)]. The ab initio calculations have been performed using quadratic configuration interaction with single and double excitation theory to build the PES. A simple scaling all correlation technique has been used to obtain a PES which yields a barrier height and reaction energy in good agreement with high level ab initio calculations and experimental measurements. Using these interpolated PESs, a detailed quasiclassical trajectory study of integral and differential cross sections, product rovibrational populations, and internal energy distributions has been carried out for the Cl+CH(4) and Cl+CD(4) reactions, and the theoretical results have been compared with the available experimental data. It has been shown that the calculated total reaction cross sections versus collision energy for the Cl+CH(4) and Cl+CD(4) reactions is very sensitive to the barrier height. Besides, due to the zero-point energy (ZPE) leakage of the CH(4) molecule to the reaction coordinate in the quasiclassical trajectory (QCT) calculations, the reaction threshold falls below the barrier height of the PES. The ZPE leakage leads to CH(3) and HCl coproducts with internal energy below its corresponding ZPEs. We have shown that a Gaussian binning (GB) analysis of the trajectories yields excitation functions in somehow better agreement with the experimental determinations. The HCl(v'=0) and DCl(v'=0) rotational distributions are as well very sensitive to the ZPE problem. The GB correction narrows and shifts the rotational distributions to lower values of the rotational quantum numbers. However, the present QCT rotational distributions are still hotter than the experimental distributions. In both reactions the angular distributions shift from backward peaked to sideways peaked as collision energy increases, as seen in the experiments and other theoretical calculations.
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Affiliation(s)
- J F Castillo
- Departamento de Química Física I, Facultad de Química, Universidad Complutense, 28040 Madrid, Spain.
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46
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Garzón A, Cuevas CA, Ceacero AA, Notario A, Albaladejo J, Fernández-Gómez M. Atmospheric reactions Cl+CH3–(CH2)n–OH (n=0–4): A kinetic and theoretical study. J Chem Phys 2006; 125:104305. [PMID: 16999524 DOI: 10.1063/1.2244556] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The reactions of Cl with a series of linear alcohols: methanol (k1), ethanol (k2), 1-propanol (k3), 1-butanol (k4), and 1-pentanol (k5) were investigated as a function of temperature in the range of 264-382 K by laser photolysis-resonance fluorescence. The obtained kinetic data were used to derive the following Arrhenius expressions: k1=(3.55+/-0.22)x10(-10) exp[-(559+/-40)T], k2=(5.25+/-0.52)x10(-11) exp[(190+/-68)T], k3=(2.63+/-0.21)x10(-11) exp[(525+/-51)T], k4=(3.12+/-0.31)x10(-11) exp[(548+/-65)T], and k5=(3.97+/-0.48)x10(-11) exp[(533+/-77)T] (in units of cm(3) molecule(-1) s(-1)). To our knowledge, these are the first absolute kinetic data reported for 1-butanol and 1-pentanol and also the first kinetic study as a function of temperature for these two compounds. Results, mechanism, and tropospheric implications are discussed and compared with the reported reactivity with OH radicals. Moreover, a theoretical insight into the mechanisms of these reactions has also been pursued through ab initio Möller-Plesset second-order perturbation treatment calculations with 6-311G** basis sets. Optimized geometries and vibrational frequencies have been obtained for transition states and molecular complexes appearing along the different reaction pathways. Furthermore, molecular energies have been calculated at quadratic configuration interaction with single, double, and triple excitations level in order to get an estimation of the activation energies.
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Affiliation(s)
- Andrés Garzón
- Facultad de CC Químicas, Universidad de Castilla La Mancha, Avenida Camilo José Cela no. 10, 13071 Ciudad Real, Spain
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47
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Rangel C, Navarrete M, Corchado JC, Espinosa-García J. Potential energy surface, kinetics, and dynamics study of the Cl+CH4→HCl+CH3 reaction. J Chem Phys 2006; 124:124306. [PMID: 16599673 DOI: 10.1063/1.2179067] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A modified and recalibrated potential energy surface for the gas-phase Cl+CH4-->HCl+CH3 reaction is reported and tested. It is completely symmetric with respect to the permutation of the four methane hydrogen atoms and is calibrated with respect to updated experimental and theoretical stationary point properties and experimental forward thermal rate constants. From the kinetics point of view, the forward and reverse thermal rate constants and the activation energies were calculated using the variational transition-state theory with semiclassical transmission coefficients over a wide temperature range of 150-2500 K. The theoretical results reproduce the available experimental data, with a small curvature of the Arrhenius plot which indicates the role of tunneling in this hydrogen abstraction reaction. A dynamics study was also performed on this PES using quasiclassical trajectory (QCT) calculations, including corrections to avoid zero-point energy leakage along the trajectories. First, we found a noticeable internal energy in the coproduct methyl radical, both in the ground-state [CH4 (v=0)] and vibrationally excited [CH4 (v=1)] reactions. This CH3 internal energy was directly precluded in some experiments or oversimplified in previous theoretical studies using pseudotriatomic models. Second, our QCT calculations give HCl rotational distributions slightly hotter than those in experiment, but correctly describing the experimental trend of decreasing the HCl product rotation excitation in going from HCl (v'=0) to HCl (v'=1) for the CH4 (v=1) reaction. Third, the state specific scattering distributions present a reasonable agreement with experiment, although they tend to make the reaction more forward and backward scattered than found experimentally probably because of the hotter rotational distribution and the deficiencies of the QCT methods.
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Affiliation(s)
- Cipriano Rangel
- Departamento de Química Física, Universidad de Extremadura, 06071 Badajoz, Spain
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48
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Troya D, Weiss PJE. Ab initio and direct quasiclassical-trajectory study of the Cl+CH4→HCl+CH3 reaction. J Chem Phys 2006; 124:74313. [PMID: 16497042 DOI: 10.1063/1.2171689] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present an electronic structure and dynamics study of the Cl + CH(4)--> HCl + CH(3) reaction. We have characterized the stationary points of the ground-state potential-energy surface using various electronic structure methods and basis sets. Our best calculations, CCSD(T) extrapolated to the complete basis-set limit based on geometries and harmonic frequencies obtained at the CCSD(T)/aug-cc-pvtz level, are in agreement with the experimental reaction energy and indirect measurements of the barrier height. Using ab initio information, we have reparametrized a semiempirical Hamiltonian so that the predictions of the improved Hamiltonian agree with the higher-level calculations in various regions of the potential-energy surface. This improved semiempirical Hamiltonian is then used to propagate quasiclassical trajectories and characterize the reaction dynamics. The good agreement of the calculated HCl rotational and angular distributions with the experiment indicates that reparametrizing semiempirical Hamiltonians is a promising approach to derive accurate potential-energy surfaces for polyatomic reactions. However, excessive energy leakage from the initial vibrational energy of the CH(4) molecule to the reaction coordinate in the trajectory calculations calls into question the suitability of the standard quasiclassical-trajectory method to describe energy partitioning in polyatomic reactions.
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Affiliation(s)
- Diego Troya
- Department of Chemistry, Virginia Tech, 107 Davidson Hall, Blacksburg, 24061-0212, USA.
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Ashfold MNR, Nahler NH, Orr-Ewing AJ, Vieuxmaire OPJ, Toomes RL, Kitsopoulos TN, Garcia IA, Chestakov DA, Wu SM, Parker DH. Imaging the dynamics of gas phase reactions. Phys Chem Chem Phys 2006; 8:26-53. [PMID: 16482242 DOI: 10.1039/b509304j] [Citation(s) in RCA: 240] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ion imaging methods are making ever greater impact on studies of gas phase molecular reaction dynamics. This article traces the evolution of the technique, highlights some of the more important breakthroughs with regards to improving image resolution and in image processing and analysis methods, and then proceeds to illustrate some of the many applications to which the technique is now being applied--most notably in studies of molecular photodissociation and of bimolecular reaction dynamics.
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Troya D. Ab initioand direct quasiclassical-trajectory study of the F+CH4→HF+CH3 reaction. J Chem Phys 2005; 123:214305. [PMID: 16356046 DOI: 10.1063/1.2126972] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present an electronic structure and dynamics study of the F+CH4-->HF+CH3 reaction. CCSD(T)/aug-cc-pVDZ geometry optimizations, harmonic-frequency, and energy calculations indicate that the potential-energy surface is remarkably isotropic near the transition state. In addition, while the saddle-point F-H-C angle is 180 degrees using MP2 methods, CCSD(T) geometry optimizations predict a bent transition state, with a 153 degrees F-H-C angle. We use these high-quality ab initio data to reparametrize the parameter-model 3 (PM3) semiempirical Hamiltonian so that calculations with the improved Hamiltonian and employing restricted open-shell wave functions agree with the higher accuracy data. Using this specific-reaction-parameter PM3 semiempirical Hamiltonian (SRP-PM3), we investigate the reaction dynamics by propagating quasiclassical trajectories. The results of our calculations using the SRP-PM3 Hamiltonian are compared with experiments and with the estimates of two recently reported potential-energy surfaces. The trajectory calculations using the SRP-PM3 Hamiltonian reproduce quantitatively the measured HF vibrational distributions. The calculations also agree with the experimental HF rotational distributions and capture the essential features of the excitation function. The results of the SRP semiempirical Hamiltonian developed here clearly improve over those using the two prior potential-energy surfaces and suggest that reparametrization of semiempirical Hamiltonians is a promising strategy to develop accurate potential-energy surfaces for reaction dynamics studies of polyatomic systems.
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Affiliation(s)
- Diego Troya
- Department of Chemistry, Virginia Tech, 107 Davidson Hall, Blacksburg, Virginia 24061-0212, USA.
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