Heat transfer in solid CO2 and N2O: dependence on temperature and volume
Abstract
Isochoric thermal conductivity of solid CO2 and N2O at temperatures of the order of and higher than the Debye temperatures (T ≳ θ) is studied. The coefficients of volume dependence of thermal conductivity are determined and used for calculating the isochoric thermal conductivity of crystals with a fixed molar volume at absolute zero. At constant pressure, the thermal resistance increases approximately in proportion to the temperature. At constant density, however, the growth of thermal resistance becomes slower with increasing temperature, and the W(T) curves show a tendency towards saturation. This effect is more pronouned in N2O, where an additional phonon scattering is caused by the dipole disordering of the crystal. The observed effect is explained by using Slack’s concept of the thermal conductivity minimum.