Pressure dependence of the optical-absorption edge of solid hydrogen in a diamond-anvil cell

Abstract

We have used a diamond-anvil cell loaded with solid ${\mathrm{H}}_{2}$ as a Fabry-Perot \'etalon. From the interference patterns of transmitted light in the visible region the dispersion of the index of refraction is determined. This is related by a dielectric model to the optical-absorption threshold energy which is found to decrease with pressure.