Two-dimensional hard dumbbells. II. Pressure in terms of free volumes and surfaces

摘要

For systems of fused-hard-sphere molecules, we relate cavity distributions to free-volume distributions and derive new statistical geometry relations between thermodynamic and cavity properties. From these results, we formulate two different approaches for calculating the pressure of systems of two-dimensional homonuclear hard dumbbells in terms of the geometry of the free volume of a molecule observed over the course of a simulation. We find a simple linear relationship to exist between the compressibility and the average of the ratio of the surface area and volume of the angle-averaged free volumes of the dumbbells. We find excellent agreement between the pressure as calculated via both approaches and the pressure as calculated from simulations. (C) 2000 American Institute of Physics. S0021-9606(00)51322-1. References: 19