Phonon dispersion of the organic semiconductor rubrene

Although various properties of organic semiconductors are believed to be strongly related to phonons, experimental examination of the lattice dynamics of organic semiconductors has been scarce. The inelastic x-ray scattering method, supported by thermal diffuse scattering and density functional theory calculations, provides the first observation of a phonon dispersion relation of the most studied organic semiconductor rubrene. The results show strong mode mixing between intra- and intermolecular modes via the strong intermolecular bonding path.