State specific dynamics of the H^-+H₂→H₂+H^- reaction: Energy resolved total reaction probabilities by the time-dependent wave packet method

Abstract

Reagent ro-vibrational state-selected and energy resolved total reaction probabilities of the title reaction are calculated on the diatomics-in-molecules potential energy surface of Belyaev et al. (Chem. Phys., 1997, 220, 43). A three dimensional time-dependent wave packet (WP) method for the total angular momentum J=0 is employed for the purpose. The reaction probabilities are obtained by the time–energy mapping of the reactive flux of the WP across a dividing surface in the asymptotic product channel. While the initial vibrational excitation of reagent H₂ is shown, in general, to decrease the reaction probability at low and moderate energies, the initial rotational excitation does not lead to any such general trend. Existence of resonances is indicated in the reaction with ro-vibrationally hot H₂ molecules. The energetic threshold and other dynamical features of the reaction are in accord with the experimental findings.