THE INTERACTION OF RARE-GAS ATOMS WITH METAL-SURFACES - A SCATTERING-THEORY APPROACH

The scattering theory formulation of the helium-metal surface interaction due to Zaremba and Kohn has been generalized to treat the entire rare gas sequence. The atom-surface repulsion is determined in terms of atomic HF T-matrix elements and is combined with a damped van der Waals interaction to produce total physisorption potentials. A systematic comparison is made between these potentials and those calculated in our earlier work based on the pseudopotential method originally developed by Harris and Liebsch. Although both formulations lead to similar trends in the calculated potentials, the latter treatment overestimates the repulsion between the adsorbate and the surface over the entire physisorption region and results in final potentials which are too shallow, particularly for the heavier rare gases. We find that our present results are in good agreement with existing experimental trends for the rare gases on various metals.