Structure and dynamics of Xe monolayers adsorbed on Cu(111) and Pt(111) surfaces studied in the density functional approach

We review theoretical treatments of physisorption of Xe on Cu(111) and Pt(111) surfaces within the recently proposed extended density functional approach that explicitly takes into account the van der Waals interactions among the constituents of adsorption systems. Based on tests of the various currently used approximations for the density functionals, and of the different treatments of long-range correlation effects which we carried out for a prototype system of a Kr dimer, we have adopted in the present study the schemes that are appropriate to systems consisting of nearly isolated fragments. In this approach the coefficients of van der Waals expansion are deduced from the DFT calculations of intrafragment electronic densities. Such generalized DFT calculations of potential energy surfaces yield a structure of Xe adlayers in good agreement with experiments and retrieve the dilation of the commensurate monolayer phase with strongly reduced intralayer Xe-Xe radial force constants. This approach provides a first principles interpretation of the observed vibrational properties of commensurate adlayers of Xe physisorbed on Cu(111) and Pt(111) surfaces.