Charge transfer and electron emission in ion–surface interactions

Abstract

The formation and decay of multiply excited projectiles during collisions of slow highly charged ions with metal and insulator surfaces have been simulated based on a classical over-barrier model. Simulations including the full trajectory of the projectile have recently allowed the simultaneous evaluation of projectile kinetic energy gains, final charge-state distributions and emitted Auger electron yields in reasonable agreement with experiments. Due to the many-electron nature of these interactions, no detailed quantum mechanical calculations are available. In contrast, for low charge states of the incident ion, quantum mechanical close-coupling calculations have been performed that provide detailed information on resonance formation, hybridization, and electron transfer, including the effects of external electric fields. In this paper, some aspects of ion–surface collisions are reviewed within both (many-electron) over-barrier models and quantum mechanical single-electron expansion methods.