Extended law of corresponding states: square-well oblates

Abstract

The vapour–liquid coexistence collapse in the reduced temperature, T r = T/T c , reduced density, ρ r = ρ/ρ c , plane is known as a principle of corresponding states, and Noro and Frenkel have extended it for pair potentials of variable range. Here, we provide a theoretical basis supporting this extension, and show that it can also be applied to short-range pair potentials where both repulsive and attractive parts can be anisotropic. We observe that the binodals of oblate hard ellipsoids for a given aspect ratio (κ = 1/3) with varying short-range square-well interactions collapse into a single master curve in the –ρ r plane, where , B 2 is the second virial coefficient, and v 0 is the volume of the hard body. This finding is confirmed by both REMC simulation and second virial perturbation theory for varying square-well shells, mimicking uniform, equator, and pole attractions. Our simulation results reveal that the extended law of corresponding states is not related to the local structure of the fluid.