Approach to electron translation in low-energy atomic collisions

We consider two conceptional problems that arise in the quantum-mechanical calculation of inelastic atomic collisions. The definition of the coupling matrix elements, which govern the inelastic transitions, seems to be ambiguous and the matrix elements can remain nonzero as the internuclear distance goes to infinity. We show that there is no ambiguity in the coupled equations, which describe inelastic collisions, and we demonstrate that the asymptotic couplings are required for a correct description of the asymptotic part of the scattering wave function. We develop on this basis a straightforward and simple procedure to deal with the asymptotic couplings in the framework of a full quantum approach and we apply it to a simple example of H+Na collisions. [S1050-2947(99)07402-8].