Thermal transport in dynamically disordered phases of molecular crystals: A thermo activation mechanism
Isochoric thermal conductivity of crystalline 1,1-difluoroethane (F-152a freon) is measured on samples of different densities in the dynamically orientationally disordered (DOD) phase. The thermal conductivity increased with temperature, similar to how it occurs in amorphous and glass-like substance...
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Veröffentlicht in: | Solid state communications 2021-04, Vol.329, p.114241, Article 114241 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | Isochoric thermal conductivity of crystalline 1,1-difluoroethane (F-152a freon) is measured on samples of different densities in the dynamically orientationally disordered (DOD) phase. The thermal conductivity increased with temperature, similar to how it occurs in amorphous and glass-like substances above the plateau area. It is found that this behavior can be described by a thermo-activation mechanism with constant activation energy and density-dependent pre-exponential factor. Bridgman coefficient g = − (∂lnκ/∂lnV)T is 6.0 ± 0.5. It is shown that the thermal conductivity of a number of other molecular crystals with the dynamic orientational disorder can be described in a similar way. Possible reasons for the thermal activation behavior of thermal conductivity are discussed.
•Isochoric thermal conductivity of crystalline 1,1-difluoroethane in the dynamic orientation disordered phase.•The hopping thermal activation mechanism with constant activation energy and a density dependence of pre-exponential factor.•The thermal conductivity of a number of other molecular disorder crystals can be described in a similar way. |
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ISSN: | 0038-1098 1879-2766 |
DOI: | 10.1016/j.ssc.2021.114241 |