Surface diffusion of heavy inert gas atoms on metals from intermolecular potential energies based on a density-functional method

Based on a recently suggested density functional, a model for corrugational inert gas atom–metal surface potential energies for intermolecular interaction is obtained. The atom–atom potential energy summation is used, from where analytical fits are obtained for the potential energies for the gas–surface systems Ar–Cu(0 0 1), Kr–Cu(0 0 1) and Ar–Ag(0 0 1). Following the solution method for the Fokker–Planck equation due to Risken, coefficients for the tracer diffusion are obtained. Finally the results are discussed concerning the characteristics of the potential energy surfaces.