Molecular-Atomic Transition in the Deuterium Hugoniot with Coupled Electron Ion Monte Carlo

TL;DR

This study uses advanced quantum Monte Carlo simulations to analyze the molecular-atomic transition in deuterium under shock compression, providing more accurate predictions of maximum compression than previous models.

Contribution

It introduces a coupled electron-ion Monte Carlo method for precise simulation of deuterium's Hugoniot, improving upon prior theoretical and experimental estimates.

Findings

Maximum compression of 4.85 at ~50 GPa

Results are ~10% higher than previous predictions

Findings are compatible within experimental uncertainties

Abstract

We have performed accurate simulations of the Deuterium Hugoniot using Coupled Electron Ion Monte Carlo (CEIMC). Using highly accurate quantum Monte Carlo methods for the electrons, we study the region of maximum compression along the principal Hugoniot, where the system undergoes a continuous transition from a molecular fluid to a monatomic fluid. We include all relevant physical corrections so that a direct comparison to experiment can be made. Around 50 GPa we found a maximum compression of 4.85, roughly 10% larger than previous theoretical predictions and experimental data but still compatible with the latter because of their large uncertainty.