Acoustic velocity and refractive index of fluid hydrogen and deuterium at high pressures

Using Brillouin scattering we have measured the pressure dependence of the accoustic velocity and refractive index of fluid hydrogen and deuterium at room temperature in a diamond anvil cell up to solidification at 55 kbars. We find good agreement between our velocities and those calculated from an equation of state given by Liebenberg et al. The refractive indices are fit by a Lorenz-Lorentz relation yielding a polarizability of 8.17±0.l×10−25 cm.3