Monte Carlo simulations of the adsorption of rare gases at high pressures

The excess surface adsorption of rare gases on the surface of a graphite crystal is calculated, at room temperature, by numerical simulations for thermodynamic states of densities covering the full domain of their fluid phases. A comparison with the measured excess surface adsorption on active carbon, in a domain of pressures from 5 to 600 MPa, shows that the experimental data are in qualitative agreement with the simulation results. When the pressure is increased, the excess surface adsorption first goes through a maximum, then decreases towards a shallow minimum, and subsequently stays constant or increases slightly up to the solid phase of rare gases in both the experiments and the simulations.