Statistical mechanics of light elements at high pressure. VII. A perturbative free energy for arbitrary mixtures of H and He

Journal Article · Fri Mar 01 00:00:00 EST 1985 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/162996· OSTI ID:5472010

Hubbard, W B; Dewitt, H E

A model free energy is presented which accurately represents results from 45 high-precision Monte Carlo calculations of the thermodynamics of hydrogen-helium mixtures at pressures of astrophysical and planetophysical interest. The free energy is calculated using free-electron perturbation theory (dielectric function theory), and is an extension of the expression given in an earlier paper in this series. However, it fits the Monte Carlo results more accurately, and is valid for the full range of compositions from pure hydrogen to pure helium. Using the new free energy, the phase diagram of mixtures of liquid metallic hydrogen and helium is calculated and compared with earlier results. Sample results for mixing volumes are also presented, and the new free energy expression is used to compute a theoretical Jovian adiabat and compare the adiabat with results from three-dimensional Thomas-Fermi-Dirac theory. The present theory gives slightly higher densities at pressures of about 10 megabars. 20 references.

• Research Organization: Arizona Univ., Tucson
• OSTI ID: 5472010
• Journal Information: Astrophys. J.; (United States), Vol. 290
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
JUPITER PLANET
THERMODYNAMICS
ADIABATIC PROCESSES
FREE ENERGY
HELIUM
HYDROGEN
MONTE CARLO METHOD
PERTURBATION THEORY
STATISTICAL MECHANICS
ELEMENTS
ENERGY
FLUIDS
GASES
MECHANICS
NONMETALS
PHYSICAL PROPERTIES
PLANETS
RARE GASES
THERMODYNAMIC PROPERTIES
640107* - Astrophysics & Cosmology- Planetary Phenomena