Energy and Angular Distributions of Electrons from FastHe++He Collisions

The first realistic calculations of the energy and angular distributions of electrons ejected in ion-atom collisions, where the ion carries along its own electrons, are presented. The calculations, within the Born-approximation framework, have been performed for ${\mathrm{He}}^{+}$ + He collisions, and measurements have also been made. Rather good quantitative agreement between our measurements and calculations has been obtained over a broad range of energies and angles. Some difficulties persist, however, near the forward direction.