Angular Distributions for a Model System of Nonadiabatic Molecular Collisions: The Quenching of Na*(3p) by H2 and D2

Abstract

Angular distributions for the electronic to vibrational-rotational and translational energy transfer process ${\mathrm{Na}}^{*}\mathrm{}\left(3p\right)+{\mathrm{H}}_2, {\mathrm{D}}_2\to \mathrm{Na}\mathrm{}\left(3s\right)+{\mathrm{H}}_2(v^{\prime }, j^{\prime })$ with product energy analysis have been measured for the first time. The differential cross sections are forward peaked, constant but small between 35° and 160°, and very slightly increasing at 180°. The observations can be qualitatively understood by a simple model for the particle motion on the attractive $\tilde{A}{}_{}{}^2{}_{}{}^{}B_2^{}{}_{}{}^{}$ excited-state surface with a hop to the repulsive $\tilde{X}{}_{}{}^2{}_{}{}^{}A_1^{}{}_{}{}^{}$ ground state.