Isochoric thermal conductivity of solid nitrogen

TL;DR

This study measures the isochoric thermal conductivity of solid nitrogen across different densities and temperatures, analyzing how molecular rotations and phonon transport influence heat conduction.

Contribution

It provides experimental data on solid nitrogen's thermal conductivity and discusses a model involving phonons and rotational modes to explain the behavior.

Findings

Thermal conductivity in alfa-N2 varies weaker than 1/T

In beta-N2, thermal conductivity increases slightly with temperature

Growth in beta-N2 attributed to decreasing rotational resistance

Abstract

The isochoric thermal conductivity of solid nitrogen has been investigated on four samples of different densities in the temperature interval from 20 K to the onset of melting. In alfa-N2 the isochoric thermal conductivity exhibits a dependence weaker than 1/T; in beta-N2 it increases slightly with temperature. The experimental results are discussed within a model in which the heat is transported by low-frequency phonons or by "diffusive" modes above the mobility boundary. The growth of the thermal conductivity in beta-N2 is attributed to the decreasing "rotational" component of the total thermal resistance, which occurs as the rotational correlations between the neighboring molecules become weaker.