Heat transfer in solid methyl alcohol

Анотація

Thermal conductivity coefficient к(T) of two crystalline (orientationally-ordered and orientationally-disordered) phases of pure methanol (at temperatures from 2 K to T_m , T_m is the melting temperature), CH₃OH + 6.6 % H₂O glass from 2 K to T_g , T_g is the glass transition temperature and a supercooled liquid from T_g to 120 K has been measured under equilibrium vapor pressure. The dependence к(T) is described approximately as a sum of two contributions: к_I(T) describing heat transport by acoustic phonons and к_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 have been compared. Different mechanisms of phonon scattering in the crystalline phases and glass have been analyzed. The к_II(T) has been calculated within the Cahill–Pohl model. There is an anomaly of the thermal conductivity of the glass state near T_g (a smeared minimum in the к(T) — curve).