Impact parameter dependence of classical capture probability from any initial state by fast bare projectiles

A model for calculating the impact parameter dependence of the single electron capture probability in fast collisions of highly charged ions and atoms is proposed. It is based on concepts suggested by Bohr and Lindhard in their classical electron capture model. In the authors' model the target atom electrons have the spatial distribution of a 'frozen' wavefunction. Using hydrogenic wavefunctions an analytic expression for the impact parameter dependence of the single electron capture probability for any target subshell is derived. Introducing this impact parameter dependence extends the applicability of the model beyond single electron capture to multielectron charge-transfer processes. The present calculations are applied to two-electron systems using the independent electron approximation.