ISOCHORIC THERMAL-CONDUCTIVITY OF SOLID F REONS OF METHANE SERIES - CF2CL2 AND CHF2CL

The isochoric thermal conductivity and the thermal pressure of solid f reons of a methane series CF2Cl2 and CHF2Cl are studied near the melti ng temperature. It is Found that the isochoric thermal conductivity of CHF2Cl increases slowly with temperature whereas in the case of CF2Cl 2 it is practically constant. A correlation is made with another repre sentatives of the methane series. The relation between the temperature dependence of thermal conductivity and the nature of orientational mo tion of ?he molecules is discussed. It is demonstrated that the behavi or of thermal conductivity in orientationally-ordered phases fitted we ll with the case of strong scattering and the concept of <<minimum>> t hermal conductivity. The increase of the isochoric thermal conductivit y in orientationally-disordered phases is accounted for by the decreas e in phonon scattering by rotational excitations due to the weakening of correlations in the rotation of neighboring molecules.