Integral equation approach to electron-hydrogen collisions

Abstract

A recent formulation of the three-body collision problem in the form of coupled multi-channel two-body Lippmann-Schwinger equations is applied to the electron-hydrogen collision problem. The relation between these equations and the close-coupling equations is studied by casting the latter into integral form. A simple high-energy approximation, which amounts to a unitary version of the Born-Oppenheimer approximation, is derived, and used in its simplest form to calculate elastic scattering. The results indicate that exchange effects and unitarity corrections are significant at least up to 400 ev.