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Yao Q, Cao XM, Zong WG, Sun XH, Li ZR, Li XY. Potential Energy Surface for Large Barrierless Reaction Systems: Application to the Kinetic Calculations of the Dissociation of Alkanes and the Reverse Recombination Reactions. J Phys Chem A 2018; 122:4869-4881. [PMID: 29757648 DOI: 10.1021/acs.jpca.8b00877] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The isodesmic reaction method is applied to calculate the potential energy surface (PES) along the reaction coordinates and the rate constants of the barrierless reactions for unimolecular dissociation reactions of alkanes to form two alkyl radicals and their reverse recombination reactions. The reaction class is divided into 10 subclasses depending upon the type of carbon atoms in the reaction centers. A correction scheme based on isodesmic reaction theory is proposed to correct the PESs at UB3LYP/6-31+G(d,p) level. To validate the accuracy of this scheme, a comparison of the PESs at B3LYP level and the corrected PESs with the PESs at CASPT2/aug-cc-pVTZ level is performed for 13 representative reactions, and it is found that the deviations of the PESs at B3LYP level are up to 35.18 kcal/mol and are reduced to within 2 kcal/mol after correction, indicating that the PESs for barrierless reactions in a subclass can be calculated meaningfully accurately at a low level of ab initio method using our correction scheme. High-pressure limit rate constants and pressure dependent rate constants of these reactions are calculated based on their corrected PESs and the results show the pressure dependence of the rate constants cannot be ignored, especially at high temperatures. Furthermore, the impact of molecular size on the pressure-dependent rate constants of decomposition reactions of alkanes and their reverse reactions has been studied. The present work provides an effective method to generate meaningfully accurate PESs for large molecular system.
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Lin HH, Yeh CT. Pressure Effect on the Interaction of Hydrogen Atoms with Ethyl Radicals. J CHIN CHEM SOC-TAIP 2013. [DOI: 10.1002/jccs.197800007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Mihelcic D, Schubert V, Höfler F, Potzinger P. Bestimmung kinetischer Isotopieeffekte der Additionsreaktion des Wasserstoffatoms an Äthylen und Propen mit Hilfe der Pulsradiolyse. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/bbpc.19750791212] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Klippenstein SJ, Georgievskii Y, Harding LB. Predictive theory for the combination kinetics of two alkyl radicals. Phys Chem Chem Phys 2006; 8:1133-47. [PMID: 16633594 DOI: 10.1039/b515914h] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An ab initio transition state theory based procedure for accurately predicting the combination kinetics of two alkyl radicals is described. This procedure employs direct evaluations of the orientation dependent interaction energies at the CASPT2/cc-pvdz level within variable reaction coordinate transition state theory (VRC-TST). One-dimensional corrections to these energies are obtained from CAS+1+2/aug-cc-pvtz calculations for CH3 + CH3 along its combination reaction path. Direct CAS+1+2/aug-cc-pvtz calculations demonstrate that, at least for the purpose of predicting the kinetics, the corrected CASPT2/cc-pvdz potential energy surface is an accurate approximation to the CAS+1+2/aug-cc-pvtz surface. Furthermore, direct trajectory simulations, performed at the B3LYP/6-31G* level, indicate that there is little local recrossing of the optimal VRC transition state dividing surface. The corrected CASPT2/cc-pvdz potential is employed in obtaining direct VRC-TST kinetic predictions for the self and cross combinations of methyl, ethyl, iso-propyl, and tert-butyl radicals. Comparisons with experiment suggest that the present dynamically corrected VRC-TST approach provides quantitatively accurate predictions for the capture rate. Each additional methyl substituent adjacent to a radical site is found to reduce the rate coefficient by about a factor of two. In each instance, the rate coefficients are predicted to decrease quite substantially with increasing temperature, with the more sterically hindered reactants having a more rapid decrease. The simple geometric mean rule, relating the capture rate for the cross reaction to those for the self-reactions, is in remarkably good agreement with the more detailed predictions. With suitable generalizations the present approach should be applicable to a wide array of radical-radical combination reactions.
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Affiliation(s)
- Stephen J Klippenstein
- Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94551-0969, USA.
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Harding LB, Georgievskii Y, Klippenstein SJ. Predictive Theory for Hydrogen Atom−Hydrocarbon Radical Association Kinetics. J Phys Chem A 2005; 109:4646-56. [PMID: 16833805 DOI: 10.1021/jp0508608] [Citation(s) in RCA: 157] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Procedures for accurately predicting the kinetics of hydrogen atom associations with hydrocarbon radicals are described and applied to a series of reactions. The approach is based on CASPT2/cc-pvdz evaluations of the orientation-dependent interaction energies within variable reaction coordinate transition state theory. One-dimensional corrections to the interaction energies are estimated from CAS+1+2/aug-cc-pvtz evaluations for the H + CH3 reaction, and a dynamical correction factor of 0.9 is applied. This corrected CASPT2 approach yields results that are within 10% of those obtained with the full CAS+1+2/aug-cc-pvtz potential for the H + CH3, H + C2H5, H + C2H3, and H + C2H reactions. New predictions are made for the H + iso-C3H7, H + tert-C4H9, H + C6H5, and H + C10H7 reactions. For the H + CH3 and H + C2H3 reactions, where the experimental values appear to be the most well-determined, theory and experiment essentially agree to within their error bars. For the other reactions, the agreement is reasonably satisfactory given the often large dispersion in the experimental results. For the reactions with saturated alkyl radicals, the theory predicts that each additional CH3 group increases the steric factor by approximately a factor of 2. In contrast, for the unsaturated radicals, the H + C6H5 and H + C10H7 high-pressure association rate coefficients are nearly identical to that for H + C2H3.
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Affiliation(s)
- Lawrence B Harding
- Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
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Pimentel AS, Payne WA, Nesbitt FL, Cody RJ, Stief LJ. Rate Constant for the Reaction H + C2H5 at T = 150−295 K. J Phys Chem A 2004. [DOI: 10.1021/jp040204s] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- André S. Pimentel
- Laboratory for Extraterrestrial Physics, NASA/Goddard Space Flight Center, Greenbelt, Maryland 20771, and Department of Chemistry, Catholic University of America, Washington, DC 20064
| | - Walter A. Payne
- Laboratory for Extraterrestrial Physics, NASA/Goddard Space Flight Center, Greenbelt, Maryland 20771, and Department of Chemistry, Catholic University of America, Washington, DC 20064
| | - Fred L. Nesbitt
- Laboratory for Extraterrestrial Physics, NASA/Goddard Space Flight Center, Greenbelt, Maryland 20771, and Department of Chemistry, Catholic University of America, Washington, DC 20064
| | - Regina J. Cody
- Laboratory for Extraterrestrial Physics, NASA/Goddard Space Flight Center, Greenbelt, Maryland 20771, and Department of Chemistry, Catholic University of America, Washington, DC 20064
| | - Louis J. Stief
- Laboratory for Extraterrestrial Physics, NASA/Goddard Space Flight Center, Greenbelt, Maryland 20771, and Department of Chemistry, Catholic University of America, Washington, DC 20064
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Zhu RS, Xu ZF, Lin MC. Ab initio studies of alkyl radical reactions: Combination and disproportionation reactions of CH3 with C2H5, and the decomposition of chemically activated C3H8. J Chem Phys 2004; 120:6566-73. [PMID: 15267548 DOI: 10.1063/1.1665370] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
This paper reports the first quantitative ab initio prediction of the disproportionation/combination ratio of alkyl+alkyl reactions using CH3+C2H5 as an example. The reaction has been investigated by the modified Gaussian-2 method with variational transition state or Rice-Ramsperger-Kassel-Marcus calculations for several channels producing (1) CH4+CH2CH2, (2) C3H8, (3) CH4CH3CH, (4) H2+CH3CHCH2, (5) H2+CH3CCH3, and (6) C2H6+CH2 by H-abstraction and association/decomposition mechanisms through singlet and triplet potential energy paths. Significantly, the disproportionation reaction (1) producing CH4+C2H4 was found to occur primarily by the lowest energy path via a loose hydrogen-bonding singlet molecular complex, H3CHC2H4, with a 3.5 kcal/mol binding energy and a small decomposition barrier (1.9 kcal/mol), instead of a direct H-abstraction process. Bimolecular reaction rate constants for the formation of the above products have been calculated in the temperature range 300-3000 K. At 1 atm, formation of C3H8 is dominant below 1200 K. Over 1200 K, the disproportionation reaction becomes competitive. The sum of products (3)-(6) accounts for less than 0.3% below 1500 K and it reaches around 1%-4% above 2000 K. The predicted rate constant for the disproportionation reaction with multiple reflections above the complex well, k1=5.04 x T(0.41) exp(429/T) at 200-600 K and k1=1.96 x 10(-20) T(2.45) exp(1470/T) cm3 molecule(-1) s(-1) at 600-3000 K, agrees closely with experimental values. Similarly, the predicted high-pressure rate constants for the combination reaction forming C3H8 and its reverse dissociation reaction in the temperature range 300-3000 K, k2(infinity)=2.41 x 10(-10) T(-0.34) exp(259/T) cm3 molecule(-1) s(-1) and k(-2)(infinity)=8.89 x 10(22) T(-1.67)exp(-46 037/T) s(-1), respectively, are also in good agreement with available experimental data.
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Affiliation(s)
- R S Zhu
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA
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Wilson EH. Current state of modeling the photochemistry of Titan's mutually dependent atmosphere and ionosphere. ACTA ACUST UNITED AC 2004. [DOI: 10.1029/2003je002181] [Citation(s) in RCA: 285] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Mousavipour SH, Homayoon Z. A Theoretical Study on the Kinetics of Disproportionation versus Association Reaction of CH3 + C2H5. J Phys Chem A 2003. [DOI: 10.1021/jp030597f] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Zahra Homayoon
- Department of Chemistry, College of Sciences, Shiraz University, Shiraz, Iran
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Perry JJ, Kim YH, Fox JL, Porter HS. Chemistry of the Jovian auroral ionosphere. ACTA ACUST UNITED AC 1999. [DOI: 10.1029/1999je900022] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Sillesen A, Ratajczak E, Pagsberg P. Kinetics of the reactions H + C2H4 → C2H5, H + C2H5 → 2CH3 and CH3 + C2H5 → products studied by pulse radiolysis combined with infrared diode laser spectroscopy. Chem Phys Lett 1993. [DOI: 10.1016/0009-2614(93)85052-p] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Cobos CJ, Troe J. The Dissociation-Recombination System CH4 + M⇌CH3 + H + M: Reevaluated Experiments from 300 to 3000 K. ACTA ACUST UNITED AC 1990. [DOI: 10.1524/zpch.1990.167.part_2.129] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Stewart PH, Smith GP, Golden DM. The pressure and temperature dependence of methane decomposition. INT J CHEM KINET 1989. [DOI: 10.1002/kin.550211005] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Yung YL, Drew WA, Pinto JP, Friedl RR. Estimation of the reaction rate for the formation of CH3O from H + H2CO: implications for chemistry in the Solar System. ICARUS 1988; 73:516-526. [PMID: 11538223 DOI: 10.1016/0019-1035(88)90061-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
It is argued that the formation of the methoxy radical (CH3O) from H + H2CO may play an essential role in the reduction of CO to CH4. The rate coefficient for this reaction has been estimated using the approximate theory of J. Troe (1977a, J. Chem. Phys. 66, 4745) and transition state theory. We briefly discuss the implications of this reaction for the chemistry of CO on Jupiter, in the solar nebula, for interpreting the laboratory experiments of A. Bar-Nun and A. Shaviv (1975, Icarus 24, 197) and A. Bar-Nun and S. Chang (1983, J. Geophys. Res. 88, 6662) and for organic synthesis in the prebiotic terrestrial atmosphere.
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Affiliation(s)
- Y L Yung
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena 91125, USA
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Zahnle KJ. Photochemistry of methane and the formation of hydrocyanic acid (HCN) in the Earth's early atmosphere. ACTA ACUST UNITED AC 1986. [DOI: 10.1029/jd091id02p02819] [Citation(s) in RCA: 193] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Bartels M, Heinemann P, Hoyermann K. The reactions of hydrogen atoms with cyclo-C3H5 and cyclo-C5H9 radicals: Rates and mechanisms at low pressure. ACTA ACUST UNITED AC 1985. [DOI: 10.1016/s0082-0784(85)80562-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Elementary reactions in the oxidation of ethylene: The reaction of OH radicals with ethylene and the reaction of C2H4OH radicals with H atoms. ACTA ACUST UNITED AC 1982. [DOI: 10.1016/s0082-0784(82)80178-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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A high pressure rate constant for CH 3 + H and an analysis of the kinetics of the CH 3 + H → CH 4 reaction. Chem Phys 1980. [DOI: 10.1016/0301-0104(80)85118-4] [Citation(s) in RCA: 23] [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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Davis DD, Smith GR, Guillory WA. Infrared laser photolysis: a new tool for the study of prebiotic chemistry. ORIGINS OF LIFE 1980; 10:237-45. [PMID: 7413184 DOI: 10.1007/bf00928401] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Infrared laser induced dielectric breakdown and multiphoton absorption experiments on CH4/NH3 'atmospheres' are described. It is found that HCN, a central intermediate in prebiotic chemistry, is a principle product. This, combined with the fact that dielectric breakdown appears to have much in common with ordinary electric sparks, suggests that the laser could be a useful tool in studies of prebiotic chemistry. Several possible experiments in this vein are suggested.
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The reactions of alkyl radicals with oxygen atoms: Identification of primary products at low pressure. ACTA ACUST UNITED AC 1979. [DOI: 10.1016/s0082-0784(79)80052-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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