Resonant two-electron processes in ion–atom collisions

A review of some of the recent results in an effort to obtain electron-ion differential scattering cross sections using fast ion-atom collisions is given. In the projectile frame, if we neglect the effects from the target nucleus, the ion-atom collision can be described as an electron-ion scattering process where the energy distribution of the impinging quasi-free electrons is determined by the Compton-profile of the target. In this electron scattering model (ESM), in addition to the direct electron scattering, doubly excited state formation of the projectile ion is also possible. This is a resonant process in which the doubly excited states can subsequently decay by ejecting Auger-electrons. We have studied elastic, inelastic and superelastic electron scattering as a function of incoming electron energy by observing the outgoing electron energy in the ion-atom collision emission spectra. (C) 1999 Elsevier Science B.V. All rights reserved.