Role of Intersystem Crossing in the Dynamics of the O(3P) + (CH3)2CHI, (CH3)3CI Reactions

Abstract

Reactive scattering of O(3P) atoms with (CH3)2CHI and (CH3)3CI molecules has been studied at an initial translational energy E ∼ 51 kJ mol-1 using a supersonic beam of O atoms seeded in He buffer gas from a microwave discharge source. Sharply backward peaked angular distributions of IO product scattering are observed with distinctly higher product translational energy for the backward compared with the forward and sideways scattering. Mildly forward and backward peaked angular distributions slightly favoring the backward direction are observed for HOI product scattering with the product translational energy distribution being independent of scattering angle. The component of IO scattering with low product translational energy and the HOI scattering are both attributed to intersystem crossing from the lowest triplet 3A‘‘ potential energy surface to a bound OIR intermediate on the singlet 1A‘ potential energy surface. The HOI product is formed via a five-membered ring transition state where the H atom is ab...