Neutron Scattering from Solid Deuterium at High Pressures and Low Temperatures.

The phonon spectrum of solid deuterium has been measured using thermal neutrons. Measurements were conducted at a pressure range up to 4.5 kbar and a temperature range between 4K and 50K. Energy shifts and linewidths were measured as functions of temperature. The latter were determined by deconvoluting the spectra from a Gaussian instrument resolution function. Mode Gruneisen (gamma)'s were measured and found to vary from 1.8 for the (110) and (100) TA(,(VBAR)(VBAR)) modes to 2.0 for the LA, LO and TO(,(VBAR)(VBAR)) modes in the symmetry directions (110) and (100).