Quasi-classical trajectory study of the adiabatic reactions occurring on the two lowest-lying electronic states of the LiH2+ system

Abstract

Quasi-classical trajectory calculations have been performed on the adiabatically allowed reactions taking place on the two lowest-lying electronic states of the LiH₂⁺ system, using the ab initio potential energy surfaces of Martinazzo et al. (J. Chem. Phys., 2003, 119, 11 241). These reactions comprise: (i) the exoergic H₂ and H₂⁺ formation occurring through LiH⁺ + H and LiH + H⁺ collisions in the ground and in the first electronically excited state, respectively; (ii) the endoergic (ground state) LiH⁺ dissociation induced by collisions with H atoms; and (iii) the endoergic (excited state) Li + H₂⁺ → LiH + H⁺ reaction. The topic is of relevance for a better understanding of the lithium chemistry in the early universe. Thermal rate constants for the above reactions have been computed in the temperature range 10–5000 K and found in reasonably good agreement with estimates based on the capture model.