Equation of state of metallic hydrogen from coupled electron-ion Monte Carlo simulations

Miguel A. Morales, Carlo Pierleoni, D. M. Ceperley

Research output: Contribution to journalArticlepeer-review

Abstract

We present a study of hydrogen at pressures higher than molecular dissociation using the coupled electron-ion Monte Carlo method. These calculations use the accurate reptation quantum Monte Carlo method to estimate the electronic energy and pressure while doing a Monte Carlo simulation of the protons. In addition to presenting simulation results for the equation of state over a large region of the phase diagram, we report the free energy obtained by thermodynamic integration. We find very good agreement with density-functional theory based molecular-dynamics calculations for pressures beyond 600 GPa and densities above ρ=1.4g/ cm3, both for thermodynamic and structural properties. This agreement provides a strong support to the different approximations employed in the density-functional treatment of the system, specifically the approximate exchange-correlation potential and the use of pseudopotentials for the range of densities considered. We find disagreement with chemical models, which suggests that a reinvestigation of planetary models-previously constructed using the Saumon-Chabrier-Van Horn equations of state-might be needed.

Original languageEnglish (US)
Article number021202
JournalPhysical Review E - Statistical, Nonlinear, and Soft Matter Physics
Volume81
Issue number2
DOIs
StatePublished - Feb 24 2010

ASJC Scopus subject areas

  • Statistical and Nonlinear Physics
  • Statistics and Probability
  • Condensed Matter Physics

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