Adsorption of argon on graphite and graphite with preadsorbed xenon monolayer: Simulation using the Monte Carlo technique

The Monte Carlo technique in the “Gibbs” ensemble is used to calculate Henry constants of adsorption of argon on graphite and graphite with preadsorbed xenon monolayer with an ideal commensurate structure. The calculation algorithm is described; it is shown that the obtained results agree well with the literature data. Simulation was carried out in the approximation of additivity of atom-atom potentials in the Lennard-Jones form (6,12) with parameters found from the properties of argon, xenon, and graphite without introducing any corrections. The results of calculations for both adsorption systems point both to translation mobility and vibrations of adsorbed argon atoms normally to the adsorbent surface. The contribution of the vibrational degree of freedom to the thermodynamic characteristics of adsorption of argon can be approximately accounted for within the harmonic oscillator model.