INSULATOR-METAL TRANSITION IN SOLID HYDROGEN - IMPLICATION OF ELECTRONIC-STRUCTURE CALCULATIONS FOR RECENT EXPERIMENTS

Electronic-structure calculations for compressed molecular hydrogen ar e performed to provide more insight into the diversity of phenomena re cently observed experimentally. We perform full-potential linearized a ugmented plane-wave calculations and analyze them in terms of a molecu lar tight-binding model. We show that sigma(g) and sigma(u) bands over lap occurs at rather low pressure, while an insulating state persists at specific orientations up to 200 GPa, in accord with previous work, and is due to opening of hybridization gaps at the Fermi level. We als o present calculations of electronic properties such as plasma frequen cies and electron-vibron coupling.