Dynamics calculations for the LiH+H⇆Li+H2 reactions using interpolations of accurate ab initio potential energy surfaces

Abstract

Complete active space self-consistent-field calculations followed by multireference configuration interaction calculations are used to generate potential energy surfaces for the reaction of LiH+H⇆Li+H2. For interpolation of the potential energy surfaces, a recently proposed interpolant moving least squares(IMLS)/Shepard scheme is used. Trajectory calculations for LiH+H→Li+H2 on the interpolated potential energy surface illustrate that the initial vibrational state of LiH plays little role probably due to the absence of the energy barrier for this reaction. The reactive cross section shows a maximum value corresponding to the initial collision energy as low as 0.03 eV. Trajectory calculations for Li+H2→LiH+H show that high vibrational excitation (ν⩾4) of H2 molecule is the most efficient way and the collision energy inefficiently induces the reaction.