Solid hydrogen. Ground-state energy,pressure, compressibility and phase transition at high densities

The ground-state energy, the pressure and the compressibility of solid molecular hydrogen is calculated by means of a modified Brueckner theory. The Bethe-Gold-stone equation is solved to give the reaction matrix or the effective interaction in coordinate space, and the ground-state energy for hcp and fcp hydrogen is calculated. Also, the pressure and the compressibility is estimated from the dependence of the ground-state energy on density or molar volume. The possibility of a phase transition from solid molecular hydrogen into a metallic atomic phase is also considered. The ground-state energy and pressure for bcc atomic hydrogen is calculated, and a phase transition is found to occur at a pressure of 1.2·10⁶ atm.