The critical temperature and properties of real gas from low order perturbed virial expansions

It is shown that a low-order expansion in powers of density about a short-range reference system, called a perturbed virial expansion, is superior to the common virial expansion and provides a reasonably accurate estimate of both the critical temperature of simple fluids and results on thermodynamics of real gas over a wider range of densities/temperatures. The results are presented for three common van der Waals hard-core models (square-well, Yukawa, and Sutherland) and for the realistic Lennard-Jones fluid.

► Extension of applicability of the virial expansion.
► Estimation of the critical temperature from the 2nd virial coefficient only.
► Correction of the ideal gas behavior at higher densities.