Bound state spectroscopy of he adsorbed on NaCl(001): Band structure effects

The interaction between atoms and surfaces may be probed by bound state resonance spectroscopy. The experiments are usually interpreted within the free particle picture which assumes that the energy-momentum relation of atoms adsorbed onto a surface is described by 2D parabolic bands. We calculate and analyze the band structure of an atom adsorbed on a model corrugated surface and follow its behavior as the interaction potential evolves from weakly to strongly corrugated. Besides the expected reduction of degeneracy and development of gaps, we obtained a sizable correction to the bound state energies. We employ our results to reanalyze the available experiments on the system He-NaCl(001).