Charge exchange to the continuum for light ions in solids

Abstract
Electron capture into ionized states of fast ions (H+, H2+, He+) in carbon and gold foils is investigated. Velocity of ejected electrons are measured in the forward direction and a characteristic cusp-shaped peak is found for electrons ejected with velocity equal to that of the incoming ions. The spectra are interpreted by a theory of charge exchange to the continuum, based on an atomic physics ion-atom collision model. As with proper charge exchange, a second order Born approximation is necessary to calculate the high energy cross sections.