Ab initio results for the adiabatic atom-surface interaction for helium and neon on a simple metal

We report an ab initio calculation of the adiabatic electronic properties of He and Ne atoms interacting with a jellium (Al-like) surface, in the framework of the embedding method and using density functional theory in the local density approximation. In particular, attention is focused on the repulsive atom-surface potential. For incident atoms with initial kinetic energies in the typical experimental range (up to about 200 meV), it is shown that Ne gets closer to the metal than He. This is in agreement with the experimental observation of a greater sensitivity to the surface electronic structure of Ne than of He, but in contrast with results obtained by simply applying the effective medium theory to the Ne/metal system.