Supercritical Crossover Lines in the Cell Fluid Model

O. A. Dobush, M. P. Kozlovskii, R. V. Romanik

Published 2024-10-31Version 1

A cell fluid model with a modified Morse potential is studied. The supercritical states are considered with respect to a possibility to build a separation boundary between liquid-like and gas-like bahaviors. Three different lines are calculated that can be used for this purpose: the locus of the isothermal compressibility maxima, the locus of the thermal expansion coefficient maxima, and the line where the effective chemical potential is zero, M=0. By the symmetry of the functionals for the partition functions, the condition M=0 in fluids is analogous to the absence of an external field in the Ising model.