The unified picture for the classical laws of Batschinski and the rectilinear diameter for molecular fluids

TL;DR

This paper unifies classical laws of Batschinski and the rectilinear diameter for molecular fluids by deriving explicit thermodynamic relations and explaining the binodal's cubic form and the Widom line's role as a phase boundary.

Contribution

It provides a unified theoretical framework linking the Batschinski laws and the rectilinear diameter for molecular fluids, including explicit relations and phase boundary explanations.

Findings

Explicit relations between lattice gas and fluid thermodynamics are derived.

The Widom line is identified as the boundary between gas-like and liquid-like states.

A global cubic form of the binodal for molecular liquids is explained.

Abstract

The explicit relations between the thermodynamic functions of the Lattice Gas model and the fluid within the framework of approach proposed earlier in [V. L. Kulinskii, J. Phys. Chem. B \textbf{114} 2852 (2010)] are derived. It is shown that the Widom line serves as the natural border between the gas-like and the liquid-like states of the fluid. The explanation of the global cubic form of the binodal for the molecular liquids is proposed and the estimate for the amplitude of the binodal opening is obtained.