Thermodynamic properties of compressed solid hydrogen

Abstract

The high-pressure thermodynamic properties of molecular and metallic hydrogen are calculated from the fundamental viewpoint of statistical mechanics. In the molecular solid phase the interaction between hydrogen molecules is taken to be an angle-dependent de Boer repulsion, fitted to the theoretical results of Hirschfelder, Magnasco, Mason, McWeeny, and Musso, with spherical attractions as calculated by Margenau. Thermo dynamic properties for the denser metallic phase are obtained from an improved self consistent version of the Wigner-Huntington calculation, in which the correlations due to electronic repulsions are more closely approximated and in which the Kohn-Sharn local exchange is used. By comparing the Gibbs free energies of the molecular solid and the metal, we predict a phase transition linking the two at 840 kbars, well within the reach of several experiments now being designed.

Structure of Jupiter and Saturn

“…Various estimates of the pressure at which the metallic phase becomes stable have been made (Wigner and Huntington, 1935;Kronig et al, 1946;Abrikosov, 1964;De Marcus, 1959;Alder, 1961;Neece et al, 1971;Trubitsyn, 1971); we shall discuss the nature of these estimates below. Meantime, we note that the value of the critical pressure at zero temperature is generally estimated at about 1.5 Mbar.…”

Anisotropic contributions to the ground-state properties of solid para-H2

“…It is convenient to describe ft in terms of atom-atom coordinates. That is, (2) where the ~ represent the distances between atoms on the two different molecules (i, ]). It is easy to see that Eq.…”

Hydrogen, 1. Properties and Occurence

“…11 Pa) a metallic, electrically conductive hydrogen phase with a density of >1.000 kg/m 3 has been reported [13][14][15]. Some properties of solid p-H 2 at the triple point are presented in Table 5.…”