Multiphase tin equation of state using density functional theory

TL;DR

This paper develops a comprehensive multiphase equation of state for tin using density functional theory, including solid and liquid phases, and validates it against experimental data for use in hydrodynamics simulations.

Contribution

It introduces a new DFT-based multiphase EOS for tin, integrating solid and liquid phase data into a tabular form for improved simulation accuracy.

Findings

High agreement with experimental phase boundary data

Accurate modeling of the melt curve of tin

EOS suitable for hydrodynamics simulations

Abstract

We perform density functional theory (DFT) calculations of five solid phases and the liquid phase of tin. The calculations include cold curves of the five solid phases, phonon calculations in the quasi-harmonic approximation over a range of volumes for each solid phase, and DFT-based molecular dynamics (DFT-MD) calculations of the liquid phase. Using the DFT results, we construct a tabular multiphase SESAME equation of state for tin, referred to as SESAME 2162. Comparisons to experimental data are made and show a high level of agreement in isobaric data, isothermal data, shock data, and phase boundary measurements, including measurements of the melt curve. The 2162 EOS will be useful for hydrodynamics simulations and has been designed with an eye toward hydrodynamics simulations that incorporate materials strength models and allow for modeling of the kinetics of phase transitions.