Lattice model of krypton and xenon submonolayers on graphite surface

Applicability of the extended cluster variation method for calculating phase diagrams of Kr and Xe adsorbed submonolayer lattice model on graphite basal surface is shown. It is also shown that the necessary condition of reproduction of experimentally observed submonolayer thermodynamic characteristics is the consideration of adsorbed atom delocalization resulted from a small deep and a flattened shape of potential wells coinciding with hexagonal cells of adsorbent surface. Therefore energy parameters of the lattice model were calculated by dint of averaging over graphite cells of potentials of adsorbed atom interaction between themselves. The consideration of filling of the nearest surrounding with adsorbed atoms permitted to simulate the dependence of energy parameters on density and temperature. Phase diagrams obtained are qualitatively similar to experimentally observed and reproduce well values of characteristic temperatures