Transition state dynamics of [formula omitted] reactive scattering

Abstract

A simple model is proposed for the direct rebound dynamics of O( 3P) atoms reacting with H 2S molecules whereby an H atom is displaced at a bending angle β with respect to the direction of the OS axis of the triplet H 2SO transition state. Comparison with the recent angular distribution measurements of HSO reactive scattering by Casavecchia et al. at an initial translational energy E = 50 kJ mol −1, suggests that the bending angle lies in the range β = 60° ± 10°, where β = 0° refers to the collinear OSH configuration. Ab initio calculations indicate a more strongly bent transition state which is initially pyramidal but passes through a planar configuration before dissociating, with the bending angle decreasing from β ≈ 96° to β ≈ 80°. Excitation of both the HSH bending and asymmetric stretch modes of the transition state results in final dissociation through less strongly bent configurations.