Phonon density of states probed by inelastic x-ray scattering

The formalism and the experimental conditions under which coherent inelastic x-ray scattering from phonons can be utilized to determine the vibrational density of states are presented. The validity of the approach is checked by comparison of results for diamond and MgO with ab initio lattice dynamics calculations and thermodynamic measurements. For diamond the agreement between experiment and theory is remarkable, while for MgO slight differences can be observed, indicating the need for further refinement of the lattice dynamics calculations. The generalization of the formalism is discussed, and potential applications in various research fields are laid out.