Equation of state of solid hydrogen and deuterium from single-crystal x-ray diffraction to 26. 5 GPa

Journal Article · Mon Oct 01 04:00:00 EDT 1990 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.42.6458· OSTI ID:6204157

Hemley, R J; Mao, H K; Finger, L W; Jephcoat, A P; Hazen, R M; Zha, C S ^[1]

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1. Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road, N.W., Washington, D.C. (USA)

Pressure-volume equations of state of solid normal hydrogen and deuterium are determined from single-crystal x-ray diffraction measurements to maximum pressures of 26.5 GPa (265 kbar) at 300 K. Experimental data for deuterium are presented and used with the previously reported results for hydrogen. The measurements for deuterium indicate that the structure remains hexagonal closed packed to at least 14.2 GPa at 300 K. The {ital P}-{ital V} data are analyzed with both phenomenological equation-of-state formalisms and pair-potential models. The thermal contributions are calculated from a Mie-Gruneisen model and from lattice-dynamics calculations using effective potentials. A {ital P}-{ital V} equation of state is determined that accurately describes both the high-pressure diffraction data (to {ital V}/{ital V}{sub 0}=0.2) and previous low-pressure compression results ({ital V}/{ital V}{sub 0}=1.0 to 0.4). There is a significant softening of the equation of state relative to the predictions of lattice-dynamics calculations using previously reported pair potentials, and several effective potentials are examined. Possible corrections to the equation of state at higher pressures, above the range of the present experiments, include effects associated with order-disorder transitions, vibron softening, and band overlap.

• OSTI ID: 6204157
• Journal Information: Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 42:10; ISSN 0163-1829; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

640302* -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
74 ATOMIC AND MOLECULAR PHYSICS
COHERENT SCATTERING
CRYSTAL STRUCTURE
DEUTERIUM
DIFFRACTION
ELEMENTS
EQUATIONS
EQUATIONS OF STATE
HYDROGEN
HYDROGEN ISOTOPES
ISOTOPES
LIGHT NUCLEI
NONMETALS
NUCLEI
ODD-ODD NUCLEI
ORDER-DISORDER TRANSFORMATIONS
PHASE TRANSFORMATIONS
SCATTERING
STABLE ISOTOPES
VERY HIGH PRESSURE
X-RAY DIFFRACTION