A systematic investigation of ionization occurring in few electron collision systems: H0, He0 impact on He

Absolute doubly differential cross sections for electron emission occurring in fast (0.5 MeV/amu) H⁰ — and He⁰ — He collisions have been measured using standard non-coincidence techniques as well as emitted electron — charge state analysed projectile coincidence techniques. The comparison of these data with results obtained for H⁺ and He⁺ impact provides insight into the influence of one or two loosely bound projectile electrons on the probabilities for projectile, target, and simultaneous projectile — target ionization. PWBA calculations for these systems demonstrate good agreement with the experimental data for target and projectile ionization and indicate the importance of including simultaneous ionization processes in the theoretical treatment.