Interactions involving two electrons in ion-atom collisions

Abstract

Two-electron processes in ion-atom collisions in which the electron-electron interaction (electron correlation) plays a role, or is expected to play a role, are considered. The processes of interest here are transfer excitation (TE), double capture, and transfer ionization (TI). For each, the importance of correlation compared to independent electron-nucleus interactions is examined. In the case of correlation, a distinction must be made between static ( after the collision) and scattering ( during the collision) correlation. In the TE process, scattering correlation can be the dominant factor; for double capture there is evidence that this mechanism plays a significant role; in the case of TI, the expected contribution from static correlation at high velocity has not yet been verified.