Phase transition in a cell fluid model

TL;DR

This paper introduces a method to describe phase transitions in a cell fluid model with pair interactions, deriving an explicit equation of state and analyzing the phase diagram using a mean-field approximation.

Contribution

It provides an exact representation of the grand partition function and an analytic form of the equation of state for the cell fluid model.

Findings

Derived an explicit equation of state applicable across a wide temperature range.

Mapped the phase diagram and coexistence curve of the cell Morse fluid.

Analyzed system behavior below and above the critical temperature.

Abstract

We propose a method of describing a phase transition in a cell fluid model with pair interaction potential that includes repulsive and attractive parts. An exact representation of the grand partition function of this model is obtained in the collective variables set. The behavior of the system at temperatures below and above the critical one is explored in the approximation of a mean-field type. An explicit analytic form of the equation of state which is applicable in a wide range of temperatures is derived, taking into account an equation between chemical potential and density. The coexistence curve, the surface of the equation of state and the phase diagram of the cell Morse fluid are plotted.