Rainbow scattering of low energetic alkalis from Ag(111)

Abstract

A study of the interaction of 10–100 eV Na and K neutrals at normal incidence from Ag(111) is presented. In the experiments the energy and angular distributions of scattered ions are measured, showing pronounced rainbows. Classical trajectory calculations using an ab initio model potential are performed and they nicely reproduce the data. These simulations indicate that entrapment effects, i.e., trapping and implantation, play an important role in the collisional processes. These effects can give rise to a maximal non-reflectivity of 50% of the crysta surface for those systems. The importance of entrapment is sensitively indicated by the occurrence of secondary rainbows.