Large-Angle, Single-Collision Scattering of Argon Ions (40-80 keV) from Metals

The energy and angular distribution of the "secondary ions" obtained from the bombardment of metallic surfaces (Cu,Ag,Au) by Ar⁺ ions (40-80 keV) shows that most of these ions arise from biparticle collisions between the incoming argon ion and a surface atom which is effectively isolated from lattice interactions. Effects attributable to multiple collisions were minimized, in the case of Cu, by the use of oriented single-crystal targets. Multiply charged species of both the projectile atoms (Ar⁺ to Ar⁶⁺) and the target atoms (1+ to 5+) were detected. Their angular distributions were qualitatively similar to those obtained in previous gas scattering experiments.