Dynamics of the reaction O(³P) + H₂S → OH + SH. 1. Rotational, Λ doublet, and fine structure distributions in the OH(ν" = 1) product

Rotational, spin-orbit, and A doublet populations have been measured in the OH(ν″ = 1) product of the O(3P) + H₂S reaction. Ground-state O atoms with kinetic energies above the barrier to reaction were formed by photolysis of NO₂ at 355 nm. Rotational populations were found to be hotter than statistically predicted, with excitation up to the energetic limit in a distribution that suggests efficient conversion of reagent kinetic energy into OH product rotation. Spin-orbit ratios show approximately equal populations in the ²∏_3/2 and ²∏_1/2 states of OH, but A doublets favor the symmetric A′ level for all measured values of N″. A model of the dynamics involving a planar transition state is invoked to explain the observations and predicts the SH cofragment to be formed in the A″ A doublet with little rotational energy.