Quantum states of he atoms adsorbed on surfaces of rare gas solids

Wave functions and energies for band states of helium atoms in the two-dimensional periodic potential at the surface of a semiinfinite rare gas solid have been studied. In the case of Kr and Ar substrates, the atoms are highly localized and, correspondingly, the band widths are small. In a third case, namely that of an argon crystal highly compressed to simulate the adsorption site density of the close-packed face of argon, much larger band widths were found. If this is a reasonable simulation, then band effects may be observable.