Equation of state and Raman-active $E_{2g}$ lattice phonon in phases I, II, and III of solid hydrogen and deuterium

TL;DR

This study combines lattice dynamics calculations with experimental data to analyze the equation of state and Raman-active phonons in solid hydrogen and deuterium across phases I, II, and III up to 2 Mbar.

Contribution

It introduces a semi-empirical many-body potential combined with density-functional theory for high-precision modeling of solid hydrogens' properties.

Findings

The potential accurately reproduces experimental data.

The pressure dependence of the $E_{2g}$ phonon is characterized.

The equation of state is reliably modeled up to 2 Mbar.

Abstract

We present results of lattice dynamics calculations of the $P-V$ equation of state and the pressure dependence of the Raman-active $E_{2g}$ lattice phonon for $p-$H$_2$ and $o-$D$_2$ in a wide pressure range up to $\sim$2 Mbar using our recently developed semi-empirical many-body potential, and density-functional theory. Comparison with existing body of experimental and theoretical results showed that the employed many-body potential is a reliable basis for high-precision calculations for phases I, II, and III of solid hydrogens.