Multichannel Harpoon Model for Reactive Quenching of Xe 5P sup 5 6P by Cl sub 2

摘要

A harpoon reaction model employing multiple crossings based on the formalism of Bauer et al and Gislason and Sachs is developed to explain the large cross sections (sigma approx.400 A sup 2 ) measured for the reaction Xe 5p sup 5 6p + Cl sub 2 . The model calculates the Landau-Zener transition probability for each intermediate ionic crossing with the covalent surface. The transition matrix elements are represented as a product of the electronic interaction (modeled by the empirical result of Olson et al) and a Frank-Condon factor for the Cl sub 2 -> Cl sub 2- transition. The model predicts near unit probability for a transition to the ionic surface for impact parameters less than 20 Bohr. Once transfer occurs, the pair is captured by dissociation of Cl sub 2- to form XeCl. The large temperature dependence observed qualitatively in the experiments is explained by the increased cross section for vibrationally excited Cl sub 2 . A simple model for orbiting collisions is used to estimate the effect of termolecular collisions. (ERA citation 13:016548)