Quasi-One-Dimensional Phase Transitions in Nanopores: Pore-Pore Correlation Effects

For adsorbates confined within a single, sufficiently narrow cylindrical pore, no phase transitions occur because the system is too close to the one-dimensional limit. We study the influence of intermolecular correlations between adsorbed molecules in neighboring cylindrical pores, using molecular simulation. For a simple model of methane in the molecular sieve $\mathrm{ALPO}{}_4-5$, we find that a phase transition between two fluid states (“gas” and “liquid”) occurs below a critical temperature that is depressed relative to the bulk value.