  Molybdenum supported thin films of ScN, MgO and NaF with a Cu adatom have
been studied in the framework of density functional theory. We have observed a
charge transfer from the metal/film interface to the Cu atom and investigated
its relation to surface and interface deformations. We find that a weak
interaction between the metal and the film is a promising prerequisite for
adatom charging. The detailed study of Cu/NaF/Mo and NaF/Mo indicates that the
distortion of the NaF film caused by the Cu adsorption has essentially
anharmonic character, as it is coupled to a strong charge redistribution in the
system.
