A novel application of kinetic Monte Carlo method in the description of N2 vapour–liquid equilibria and adsorption

Abstract

We present a novel application of kinetic Monte Carlo (kMC) to describe vapour–liquid equilibria (VLE), vapour–solid equilibria (VSE) and adsorption of nitrogen on a flat graphite surface and in graphitic slit pores. This method is applied, for the first time, to molecules having Lennard-Jones sites and fixed partial charges. For the bulk phase equilibria, we have found that all the thermodynamic properties agree well with experimental data and pre-existing simulations over a wide range of temperatures. A major advantage of the kMC method is its excellent performance under conditions where the Gibbs ensemble simulation fails to achieve convergence, especially in dense phases. Moreover, the calculation of the chemical potential is incorporated in the scheme, which avoids the need for tedious additional procedures, such as the Widom method, required in conventional methods, which add significant computational overheads. For adsorption on a graphite surface, the kMC results are superior to those from a conventional GCMC simulation under conditions where dense phases exist; this is attributed to efficient sampling of the kMC scheme.