Simulation studies of sorption in model cylindrical micropores

Simulations of the thermodynamic properties of simple gases in straight-walled cylindrical micropores are discussed. To begin, various models used for the gas atom/pore wall interaction energy are presented. These include the hard-wall cylinder, the interaction in a completely smooth but attractive/repulsive cylinder that is obtained by integrating over Lennard–Jones sitewise interactions, and those generated by summing over Lennard–Jones atoms in the solid surrounding the cylinder. Simulations of such systems are described, particularly those carried out using the Grand Canonical Monte Carlo algorithm since these yield sorption isotherms as well as energies. The isotherms generally show condensation/evaporation vertical steps and, for reasonable starting conditions, hysteresis loops. The variations in these characteristic parts of the isotherms with temperature, pore diameter and gas/pore wall interaction strength and heterogeneity will be discussed.