Isotope effects in dense solid hydrogen: Phase transition in deuterium at 190±20 GPa

Abstract

Raman measurements of solid normal deuterium compressed in a diamond-anvil cell indicate that the material undergoes a structural phase transformation at 190±20 GPa and 77 K. Spectroscopically, the transition appears analogous to that observed in hydrogen at 145±5 GPa. The large isotope effect on the transition pressure suggests there is a significant vibrational contribution to the relative stability of the solid phases of hydrogen at very high densities.