THE GRAND-CANONICAL ENSEMBLE MONTE-CARLO SIMULATION OF NITROGEN ON GRAPHITE

The adsorption of N2 molecules on the basal plane of graphite was comp uter simulated by the canonical (CMC) and grand canonical (GCMC) ensem ble Monte Carlo methods. The dependence of the average energy of adsor ption on coverage obtained by the CMC method coincides with the result s of independent molecular dynamics simulations. The isotherm of adsor ption obtained by the GCMC method is close to the experimental data. T he small deviations of the simulated isotherm from the experiment in t he submonolayer region may be explained by the residual heterogeneity of the real surface of graphite. The deviation in the region of the se cond layer is probably due to the many-body interactions which were no t properly taken into account in the computer simulations The results for the rigid nonspherical model of N2 are compared to those for a sph erical model.