Modified Virial Expansion and the Equation of State

We propose a new method for constructing the virial series, in which the expansion in terms of the density is carried out along the line of the unit compressibility factor. This approach greatly simplifies the form of high-order virial coefficients and allows us, by extrapolation, to sum up the entire virial series and obtain the corresponding equation of state. Within our approach, it is shown that the line of the unit compressibility factor is straight. Our approach is applicable to an arbitrary system or substance. The Lennard-Jones system is considered as an example. The critical parameters of this system were found, which agree with the data of numerical simulation. DOI 10.1134/S1061920821020023