Thermal conductivity of glassy primary mono-hydroxylalcohols

Thermal conductivity κ(T) data for homologous series of primary mono-hydric alcohols – methanol, ethanol, 1-propanol, 1-butanol – within their molecular glass states are analyzed within the temperature region stretching from 2 K up to the glass transition T_g. Below 7 K κ(T) increases with the number of carbon atoms in the molecule. Furthermore, its temperature dependence exhibits a behavior akin to that predicted by the phenomenological model of soft potentials (SPM). The data are then rationalized in terms of the SPM parameters such as characteristic energy W and the parameter ¯С which measures the strength of the coupling of acoustic modes with two-level systems. The dependence of such parameters upon the molecular mass of the alcohol seems to agree with the SPM predictions. The parameters ¯С and W were used to calculate the boson peak energies. The values obtained agree well with literature data.