Molecular association-mediated micropore filling of supercritical Xe in a graphite slit pore by grand canonical Monte Carlo simulation

Cluster formation of Xe molecules in a slit-shaped graphitic micropore was studied by a grand canonical Monte Carlo (GCMC) simulation and adsorption measurement at 300 K above the critical temperature of Xe. GCMC simulated and experimental adsorption isotherms indicate a strong Xe–Xe interaction, inducing cluster formation. We applied cluster analysis to the simulated adsorption isotherm for the pore width w=0.9 nm. Just after the steep rise at 75.5 kPa, a wide distribution of cluster size was observed. The growth of small Xe clusters provides the steep rise in the Xe adsorption isotherm. The intra-cluster radial distribution function is helpful for determining the possible cluster geometries.