Critical isotherms from virial series using asymptotically consistent approximants

We consider the low-density equation of state of a fluid along its critical isotherm. An asymptotically consistent approximant is formed having the correct leading-order scaling behavior near the vapor-liquid critical point, while retaining correct low-density behavior as expressed by the virial equation of state. The formulation is demonstrated for the Lennard-Jones fluid, and models for helium, water, and n-alkanes. The ability of the approximant to augment virial-series predictions of critical properties is explored, both in conjunction with and in the absence of critical-property data obtained by other means. Given estimates of the critical point from molecular simulation or experiment, ∗electronic mail: [email protected]