Quasiclassical trajectory scattering calculations for the OH + O → H + O2 reaction: Cross sections and rate constants

We report quasiclassical trajectory studies of the OH + O → H + O2 reaction using a recently developed ab initio potential energy surface for the ground electronic state of HO2. The J = 0 total reaction probability is in good agreement with the quantum result. Integral cross sections show no energy threshold and decrease as the collision energy increases. Rate constants have been calculated in the (1–500 K) temperature range. They exhibit a negative temperature dependence for temperatures above 50 K, and the thermal rate constant is in quantitative agreement with the most recent experimental data. The reactivity is slightly enhanced by rotational excitation of OH.