Published online by Cambridge University Press: 15 February 2011
We report Canonical (NVTMC), Grand Canonical (GOMC) and Gibbs Ensemble Monte Carlo (GEMC) simulations for adsorption of methane on graphite. Lennard-Jones (LJ) potentials are used for the intermolecular interactions, and both structured and structureless (10–4–3) solid-fluid potentials are considered. Several sets of methane-methane L.I parameters have been used in the literature, and we compare results obtained with these sets throughout our simulations. The adsorption isotherm and isosteric heat curve are obtained at 77.5 K and found in good agreement with experiments. The commensurateincommensurate transition (CIT) of methane on a graphite substrate with periodically varying adsorbate-adsorbent potential at 40.0 K is studied and is in qualitative agreement with experiment. The effect of varying the corrugation of the fluid-wall potential on the commensurate and incommensurate phases is explored. The GEMC simulations have been carried out to study the vapor-liquid equilibrium (VLE) of a two-dimensional (2D) LJ fluid with system sizes up to 3000 particles. The effect of system sizes on the critical behavior is investigated. The GEMC method has also been successfully applied to study the VLE in 2D adsorbed films for the first time.