Quasiclassical trajectory study of Li2(v⩽ 25,j⩽ 100)-Na exchange reaction

Abstract

The effect of high initial vibrational (v = 0-25) and rotational (j = 0-100) excitation of the reactant molecule on the cross-section σR for the reaction Li2 + Na → LiNa + Li at a relative translational energy (E trans) of 0·5 eV has been investigated using the three-dimensional quasiclassical trajectory method on the recently proposed Varandas-Morais-Pais (VMP) potential. σR increases almost linearly with increase in v, but it remains unaltered, within the statistical error, with increase in j for j = 0-30. For the higher j states, there is an increase in σR with increase in j, and the rotational enhancement gets larger with increase in v, becoming comparable to the vibrational enhancement at v = 20. The dependence of σR on E trans over the range 0·18 - 0·85 eV has been examined for v = 0, j = 0. For E trans ⩽ 0·25 eV, all trajectories get trapped. For higher E trans, σR rises to a maximum and then levels off. Comparison of our results with those on the Whitehead-Grice (WG) potential reveals that the reactivity is larger on the VMP potential than on the WG for the low v while the opposite is true for the higher v.