Brillouin and Raman scattering of fluid and solid hydrogen at high pressures and temperatures

The Brillouin and Raman scattering spectra of fluid and solid hydrogen at high pressures (2-14 GPa) and temperatures (293-520 K) were measured to investigate the intermolecular interaction in the fluid and solid states. A Benedict type of equation of state was determined in P less than or equal to 15 GPa, T less than or equal to 550 K for fluid hydrogen with an average deviation of 1.0% from existing experimental data. We examined three types of intermolecular potential, and found that the Hemley-Silvera-Goldman potential gives superior fits to experimental data over a wide temperature range above 5 GPa. It was also found that the effect of intrinsic mode anharmonicity becomes significant at high temperatures for solid hydrogen.