Influence of rotational motion of molecules on the thermal conductivity of solid SF6, CHCl3, C6H6, and CCl4

TL;DR

This study investigates how molecular rotational motion affects the thermal conductivity of solid SF6, CHCl3, C6H6, and CCl4, revealing that increased molecular freedom reduces phonon-rotation thermal resistance.

Contribution

It introduces a modified method to separate phonon-phonon and phonon-rotation contributions to thermal resistance in solids with molecular rotations.

Findings

Phonon-rotation contribution decreases with increased molecular freedom.

Thermal conductivity varies with temperature and molecular motion.

Method allows quantification of rotational effects on thermal transport.

Abstract

The thermal conductivity of solid SF6, CHCI3, C6H6, and CCl4 was investigated by the linear-flow method under saturated vapor pressures in the temperature range from 80 K to the corresponding melting temperatures and then recalculated for a constant density of the samples.The contributions of the phonon -phonon and phonon -rotation interactions to the total thermal resis tance were separated using the modified method of reduced coordinates.It is shown that the phonon- rotation contribution to the thermal resistance of the crystals decreases as the rotational motion of the molecules attains more freedom.