Influence of rovibrational excitation on the non-diabatic state-to-state dynamics for the Li(2p) + H(2) → LiH + H reaction

The non-adiabatic state-to-state dynamics of the Li(2p) + H(2) → LiH + H reaction has been studied using the time-dependent wave packet method, based on a set of diabatic potential energy surfaces recently developed by our group. Integral cross sections (ICSs) can be increase more than an order of magnitude by the vibrational excitation of H(2), whereas the ICSs are barely affected by the rotational excitation of H(2). Moreover, ICSs of the title reaction with vibrationally excited H(2) decrease rapidly with increasing collision energy, which is a typical feature of non-threshold reaction. This phenomenon implies that the title reaction can transformed from an endothermic to an exothermic reaction by vibrational excitation of H(2). With the increase of the collision energy, the sideways and backward scattered tendencies of LiH for the Li(2p) + H(2)(v = 0, j = 0, 1) → LiH + H reactions are enhanced slightly, while the backward scattering tendency of LiH for the Li(2p) + H(2)(v = 1, j = 0) → LiH + H reaction becomes remarkably weakened. For the reaction with vibrationally excited H(2) molecule, both direct and indirect reaction mechanism exist simultaneously.