An examination of substituent effects on the reaction of OH radicals with HXCO (where X=H, F, and Cl)

Abstract

In the present work, ab initio molecular orbital theory have been used in the study of the reaction of OH radicals with HXCO (where X=H, F, and Cl). Equilibrium geometries and transition state structures have been fully optimized at the unrestricted Hartree–Fock (UHF)/6-31G*, unrestricted Mo/ller–Plesset (UMP2)/6-31G* and UMP2/6-311G** levels of theory. Activation energy barriers and heats of reaction have been estimated using fourth-order Mo/ller–Plesset perturbation theory with spin projection including single, double, triple, and quadruple excitations with extended basis sets. Transition state theory treatment of the kinetics of these reactions is performed and is used to estimate the rate coefficient at 299.3 K. The results for the OH+H2CO reaction show reasonable agreement with experiment.