Heat transfer in solid methyl alcohol

The thermal conductivity coefficient kappa(T) is measured under equilibrium vapor pressure for two crystalline phases of pure methanol (orientationally ordered and orientationally disordered) at temperatures from 2 K to the melting temperature T-m and also for a CH3OH+6.6% H2O glass from 2 K to the glass transition temperature T-g and in the supercooled liquid from T-g to 120 K. The dependence kappa(T) is described approximately as a sum of two contributions: kappa(I)(T), describing heat transport by acoustic phonons, and kappa(II)(T)-by localized high-frequency excitations. The temperature dependences of the thermal conductivity of primary monoatomic alcohols CH3OH, C2H5OH, and C3H7OH in the glass state are compared. Different mechanisms of phonon scattering in the crystalline phases and glass are analyzed. The kappa(II)(T) contribution is calculated within the Cahill-Pohl model. There is an anomaly of the thermal conductivity of the glass state near T-g (a smeared minimum on the kappa(T) curve). (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3115810]