Atomic scattering potentials for an aluminum surface: Test of ab initio calculations

Atom-surface potentials entering the calculations of fast atom scattering at surfaces are often taken to be purely repulsive and parameterized by variants of the ZBL potential. However, such surface potentials derived from pairwise superpositions of binary potentials fail to reproduce recent rainbow scattering measurements performed for various atomic projectiles above different faces of atomically flat single crystal Al surfaces. It was found that the dependence of the rainbow angle θ_rb on the projectile’s kinetic energy component normal to the surface E_⊥ varies with the electronic structure of the projectile as well as with the crystallographic face of the aluminum surface. We determine static atom-surface potentials by ab initio methods which show fair agreement with the experiment.