Isochoric thermal conductivity of solid nitrogen

The isochoric thermal conductivity of solid nitrogen is investigated on four samples of different densities in the temperature interval from 20 K to the onset of melting. In alpha-N-2 file isochoric thermal conductivity exhibits a dependence weaker than Lambda proportional to 1/T; in beta-N-2 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 edge. The growth of the thermal conductivity in beta-N-2 is attributed to (lie decreasing "rotational" component of the total thermal resistance, which occurs as the rotational correlations between the neighboring molecules become weaker. (C) 2005 American Institute of Physics.