A study of low-energy differential ion-atom scattering. II. Calculations: Li+-Na

For pt.I see ibid., vol.15, p.3695 (1982). Differential cross sections for elastic Li + -Na collisions in the energy range 17<E CM <103 eV have been calculated from theoretical potentials and couplings by combining the impact parameter method with (a) a semiclassical and (b) a quantum mechanical cross section formula. Results of both calculations deviate significantly from each other. The quantum result is discussed in terms of an analytic model showing the general features of the specific case. The semiclassical formula is shown to be inapplicable to scattering at low energies (below say 200 eV) for systems exhibiting large inelastic cross sections. In an accompanying paper the quantum result is demonstrated to agree well with experiment.