Electron capture to excited states in H+ collisions with H and He

A distorted wave approximation, originally introduced by Bassel and Gerjuoy, has been used to calculate cross sections for electron capture into excited states in H+/H and H+/He collisions. The main obstacle to the use of distorted wave methods, arising from the complexity of the analytic calculations when excited states are involved, has been overcome by the use of a symbolic manipulation program. Analytic errors are thereby minimized. The results indicate that over a wide range of collision energy (20-200 keV) the distorted wave approximation provides a very satisfactory description of the collision process. (orig.)