Investigation of hydrogen, deuterium, and helium melting curves to high temperature and pressure
The melting curves of the normal phases of hydrogen and deuterium, and helium have been measured to 370 K and 110 kbar, by developing a beryllium-copper cryogenic press with a diamond anvil high pressure cell for in-situ optical measurements of matter under pressure. To describe the melting lines of hydrogen and deuterium, two modified Simon equations are proposed. The Debye temperatures and compressibilities along the melting curves are calculated. While the hydrogen data are in good agreement with the theoretically calculated values, the deuterium and helium data are not. An analysis, based on empirically derived solid and liquid equations of state, suggests that an underestimation of the liquid phase Gibbs free energy may be responsible for the approx.11% overestimation of the calculated melting pressure at 300 K for deuterium, and that the good agreement between the experimental and theoretical results in hydrogen may be fortuitous. The discrepancies between the theory and experiment, in helium, are likely due to the inadequacies associated with the assumed simple pair potential and the treatment of low temperature quantum effects. In addition, the hydrogen results provide the first independent check on the validity of the ruby pressure scale at low temperature.
- Research Organization:
- Houston Univ., TX (USA)
- OSTI ID:
- 5092400
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
DEUTERIUM
MELTING
HELIUM
HYDROGEN
COMPARATIVE EVALUATIONS
COMPRESSIBILITY
DEBYE TEMPERATURE
EQUATIONS OF STATE
EXPERIMENTAL DATA
FREE ENTHALPY
LIQUIDS
MEDIUM TEMPERATURE
SOLIDS
VERY HIGH PRESSURE
DATA
ELEMENTS
ENERGY
EQUATIONS
FLUIDS
GASES
HYDROGEN ISOTOPES
INFORMATION
ISOTOPES
LIGHT NUCLEI
MECHANICAL PROPERTIES
NONMETALS
NUCLEI
NUMERICAL DATA
ODD-ODD NUCLEI
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
RARE GASES
STABLE ISOTOPES
THERMODYNAMIC PROPERTIES
640460* - Fluid Physics- Other Quantum Fluids