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Canonical statistical adiabatic channel model calculations of the H + CH 3 → CH 4 recombination reaction on an ab initio potential energy surface. The role of the transitional modes
Author(s) -
Cobos C. J.
Publication year - 1989
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.550210303
Subject(s) - chemistry , adiabatic process , potential energy surface , ab initio , anharmonicity , quartic function , degenerate energy levels , ab initio quantum chemistry methods , reaction rate constant , potential energy , thermodynamics , atomic physics , quantum mechanics , physics , molecule , mathematics , organic chemistry , kinetics , pure mathematics
The canonical formalism of the statistical adiabatic channel model is used to calculate limiting high pressure rate constants for the H + CH 3 → CH 4 recombination reaction on a recently reported analytic potential energy surface based on ab initio calculations. An effective adiabatic channel potential which incorporates the G ϕϕ matrix element of the twofold degenerate H 3 CH transitional bending mode, quartic anharmonicity, and state selected mode coupling effects is implemented. The rate constants calculated over the temperature range 200–1000 K are in very good agreement with recent canonical variational transition state theory calculations performed on the same surface. The comparison with experimental results is also discussed.