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A phase‐space method for arbitrary bimolecular gas‐phase reactions: Application to the CH 3 CHO+HO and CH 3 OOH+HO reactions
Author(s) -
Gross A.,
Mikkelsen K. V.,
Stockwell W. R.
Publication year - 2001
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.1404
Subject(s) - chemistry , phase space , reaction rate constant , gaussian , perturbation theory (quantum mechanics) , quantum , basis set , gas phase , molecule , thermodynamics , computational chemistry , atomic physics , quantum mechanics , physics , density functional theory , kinetics , organic chemistry
A new method based upon phase‐space methods presented in Ref. 1 (Gross, A.; Mikkelsen, K. V., Stockwell, W. R. Int J Quantum Chem 2001, accepted) has been tested on the reactions CH 3 CHO+HO→CH 3 CO+H 2 O and CH 3 OOH+HO→ products . The method has been used to calculate cross sections, and rate constants in the temperature range 200–550 K. The method requires knowledge of the system's reaction and product channels for the interacting species, the vibrational frequencies, the moments of inertia, and the potential energies of the molecules in their ground state equilibrium configuration. Furthermore, the long‐range potential between the reactant and product species is required. Due to the lack of experimentally determined spectroscopic data and potential energies for the reactants and products, these values have been calculated using electronic structure theory. We have used the many‐body second‐order Møller Plesset perturbation theory (MP2) for the treatment of electron correlation in the molecules, together with two different Gaussian‐type orbital (GTO) basis sets 6‐31G and 6‐31G*. The calculated rates are compared with the experimental data estimated earlier elsewhere. On the basis of our limited tests, the method appears to yield rate constants that are within a factor of 10–25 at 300 K of the true value, which is much more accurate than currently used empirical estimation methods. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001