35 research outputs found
Isochoric thermal conductivity of solid nitrogen
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.Comment: Postscript 12 pages, 3 figures, 1 table. To be published in 200
Single-molecule characterization of extrinsic transcription termination by Sen1 helicase
Isochoric thermal conductivity of solid furan
Thermal conductivity of solid furan has been measured at isochoric conditions in the high-temperature orien-tationally-disordered phase I for samples of different densities. Our isochoric data show a gradual increase of ΛV with temperature whereas isobaric thermal conductivity goes down in this temperature range. The above effect is most clearly expressed in furan, where the atoms in the ring plane are not equivalent, as compared with earlier studied C₆H₆ and C₆H₁₂. The increase of ΛV with temperature can be attributed to weakening of the translation-al-orientational interaction which, in turn, leads to a decrease of phonon scattering on rotational excitations. The experimental data are described in terms of a modified Debye model of thermal conductivity with allowance for heat transfer by both low-frequency phonons and ―diffuse‖ modes