Metallization of solid hydrogen at megabar pressures: A first-principles quasiparticle study

Quasiparticle calculations have been performed for the band gap of solid molecular hydrogen in the hcp structure. The calculations predict that the orientationally ordered phase undergoes metallization due to an indirect band overlap at the volume V=2.50 ${\mathrm{cm}}^3$/mol and the orientationally disordered phase at V=1.89 ${\mathrm{cm}}^3$/mol, which correspond to metallization pressures of 151 and 300 GPa, respectively. A quantitative relation between the degree of orientational order and the metallization volume is obtained.