Phonon scattering and heat transfer by “ diffusive ” modes in solid C 6 H 6 ∗

The isochoric thermal conductivity of solid C6H6 is described within a model in which the heat is transferred by phonons and above the phonon mobility edge by “diffusive” modes migrating randomly from site to site. The mobility edge ω0 is found from the condition, that the phonon mean-free path restricted by the examined mechanisms of scattering cannot become smaller than half the wavelength. The contributions of phononphonon, one and two-phonon scattering to the total thermal resistance of solid C6H6 are calculated under the assumption of additive contribution of different scattering mechanisms. Significant deviations from the dependence Λ ∝1/T are explained by thermal conductivity approaching its lower limit.