Generalized linear isotherm regularity equation of state applied to metals

TL;DR

This paper introduces a new three-parameter equation of state based on the generalized Lennard-Jones potential that avoids unphysical oscillations and negative pressures at high pressures, outperforming existing models for metals.

Contribution

The proposed GLIR EOS extends previous linear isotherm regularity models, providing a more accurate and physically consistent description of metallic solids under high pressure.

Findings

GLIR EOS eliminates negative pressure issues at high pressures.

GLIR EOS fits experimental data better than previous models.

Existing EOSs show unphysical turning points and negative pressures.

Abstract

A three-parameter equation of state (EOS) without physically incorrect oscillations is proposed based on the generalized Lennard-Jones (GLJ) potential and the approach in developing linear isotherm regularity (LIR) EOS of Parsafar and Mason [J. Phys. Chem., 1994, 49, 3049]. The proposed (GLIR) EOS can include the LIR EOS therein as a special case. The three-parameter GLIR, Parsafar and Mason (PM) [Phys. Rev. B, 1994, 49, 3049], Shanker, Singh and Kushwah (SSK) [Physica B, 1997, 229, 419], Parsafar, Spohr and Patey (PSP) [J. Phys. Chem. B, 2009, 113, 11980], and reformulated PM and SSK EOSs are applied to 30 metallic solids within wide pressure ranges. It is shown that the PM, PMR and PSP EOSs for most solids, and the SSK and SSKR EOSs for several solids, have physically incorrect turning points, and pressure becomes negative at high enough pressure. The GLIR EOS is capable not only of overcoming the problem existing in other five EOSs where the pressure becomes negative at high pressure, but also gives results superior to other EOSs.