Highly charged ion-induced potential electron emission from clean Au(111): Dependence on the projectile angle of incidence

Abstract Total yields for electron emission from an atomically clean Au(1 1 1) surface bombarded by slow highly charged Ar q + ( q  ⩽ 17) and Xe q + ions ( q  ⩽ 50) have been measured as a function of ion impact angle ( θ  = 10–70°) with respect to the surface normal. For fixed ion impact velocity the electron yields which are dominated by potential electron emission increase with the inverse square root of cos( θ ). We demonstrate that for given ion species the impact velocity component normal to the surface is the key parameter for potential electron emission from metal targets.