Quasiclassical trajectory study of Li<SUB>2</SUB> (v&#8804;25,j&#8804;100)-Na exchange reaction

The effect of high initial vibrational (v=0-25) and rotational (j=0-100) excitation of the reactant molecule on the cross-section &#963;R for the reaction Li2+Na&#8594;LiNa+Li at a relative translational energy (Etrans) of 0.5 eV has been investigated using the three-dimensional quasiclassical trajectory method on the recently proposed Varandas-Morais-Pais (VMP) potential. &#963;R 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 &#963;R 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 &#963;R on Etrans over the range 0.18-0.85 eV has been examined for v=0, j=0. For Etrans&#8804;0.25 eV, all trajectories get trapped. For higher Etrans, &#963;R 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