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Statistical mechanics of light elements at high pressure. VII - A perturbative free energy for arbitrary mixtures of H and HeA 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.
Document ID
19850048726
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Hubbard, W. B. (Arizona, University Tucson, AZ, United States)
Dewitt, H. E. (California, University Lawrence Livermore National Laboratory, Livermore, CA, United States)
Date Acquired
August 12, 2013
Publication Date
March 15, 1985
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 290
ISSN: 0004-637X
Subject Category
ASTROPHYSICS
Funding Number(s)
CONTRACT_GRANT: NSG-7045
CONTRACT_GRANT: NAGW-192
Distribution Limits
Public
Copyright
Other