Continuum distorted wave approximation; resonant charge transfer by fast protons in atomic hydrogen

Abstract

The boundary conditions in the impact parameter treatment of ion-atom collisions are examined. It is shown that the Coulomb interaction between the bound electron and the incident ion gives rise to a phase term which is not included in previous treatments of this problem. A new approximation, which takes account of this phase, is presented and applied to the resonant capture process H+ + H(1s) -> H(1s) + H+. First and second order cross sections are shown to have the asymptotic energy dependence of the impulse and second Born approximations, respectively.