Phonon line shapes and excitation energies

B Fåk, B Dorner - Physica B: Condensed Matter, 1997 - Elsevier
The basis for and consistency of fitting functions for anharmonic phonons in condensed
matter as observed by inelastic neutron scattering is examined. We suggest that solids and
liquids can be described by the same fitting function. The interpretation of the parameter that
represents the excitation energy is discussed using sum rules and other physical arguments,
and its importance is illustrated for a few real systems.