Thermal conductivity of solid cyclohexane in orientationally ordered and disordered phases

Thermal conductivity ΛP of solid cyclohexane is measured at a pressure P = 0.1 MPa in the temperature range from 80 K to the melting point, which covers the ranges of low-temperature orientationally ordered phase II and high-temperature orientationally disordered phase I. Thermal conductivity ΛV is measured at a constant volume in orientationally disordered phase I. The thermal conductivity measured at atmospheric pressure decreases with increasing temperature as ΛP ∝ T−1.15 in phase II, whereas ΛP ∝ T−0.3 in phase I. As temperature increases, isochoric thermal conductivity ΛV in phase I increases gradually. The experimental data are described in terms of a modified Debye model of thermal conductivity with allowance for heat transfer by both phonons and "diffuse" modes.