Inelastic neutron scattering from solid molecular hydrogen at various densities

We have measured the inelastic neutron scattering spectra of solid para-hydrogen at T=19.3T=19.3 K as a function of the sample pressure up to 636 bar, using the crystal-analyzer inverse-geometry spectrometer TOSCA-I (ISIS, Rutherford Appleton Laboratory, UK). From the experimental spectra we have extracted the densities of phonon states and studied their evolution along with the sample density. Results have been compared with the estimates available in the literature. The present determinations improve substantially the previous experimental scenario from the point of view of both statistics and accuracy