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Experimental and calculational equation of state and melting curve of CeH2−3

Garrett Zeff1,*, Brenden W. Hamilton1, William T. Buttler1, James Hammerberg1, Rostislav Hrubiak2, and Blake T. Sturtevant1

  • *Contact author: gzeff@lanl.gov
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Phys. Rev. B 114, 144105 – Published 14 September, 2026

DOI: https://doi.org/10.1103/gglf-wx5w

Abstract

Diamond anvil cell synchrotron x-ray diffraction experiments, molecular dynamics, density functional theory, and Lindemann melting theory were used to investigate the compressibility and melting properties of CeH2−3. Ambient-temperature synchrotron x-ray diffraction measurements were made in diamond anvil cells up to a peak pressure of 20 GPa and show no indication of a first-order phase transition over this pressure range. Equation-of-state fits to the diamond anvil cell data constrain the isothermal bulk modulus, B0, to the range 76.7(51)–87.2(39) GPa. Molecular dynamics and density functional theory were employed to simulate compression curves to a peak pressure of ∼30 GPa, and constrain B0 to the range 71.6(12)–81.9(12) GPa. Using laser-heated diamond anvil cells, five melt points were measured at pressures between roughly 2 and 10 GPa. We report an experimentally determined zero-pressure melting temperature of 1737(75) K and dT/dP=27(15) K/GPa. A high-pressure melting curve generated from molecular dynamics simulations shows linear behavior between 0.5 GPa and the peak simulated pressure of 5 GPa, with a fit slope of dT/dP=16 K/GPa over this range. Calculations based on Lindemann melting theory yield a zero-pressure melting temperature of 1609 K and a slope of dT/dP=44 K/GPa for CeH2.

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Phys. Rev. B 114, 144105– Published 14 September, 2026
  • Received 28 April 2026
  • Revised 20 July 2026
  • Accepted 19 August 2026
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