New thermal conductivity mechanism in triclinic 4-bromobenzophenone crystal

• Published in: Chemical physics letters Vol. 647; pp. 55 - 58
• Main Authors: Strzhemechny, M.A., Krivchikov, A.I., Jeżowski, A., Zloba, D.I., Buravtseva, L.M., Churiukova, O., Horbatenko, Yu.V.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-03-2016
• ISSN: 0009-2614; 1873-4448
• DOI: 10.1016/j.cplett.2016.01.001

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•Thermal conductivity κ of 4-bromobenzophenone (4-BrBP) crystal was measured from 5 to 303K.•Above 130K, κ increases with T, in contrast to many other neat molecular crystals.•Excess heat flow at high T follows an activation law with energy of about 700K.•Comparison with other crystals (pristine benzophenone and monoclinic 4-BrBP).•Final conclusion: activation agent responsible for the effect is the C–Br stretch mode.
Thermal conductivity κ of a single crystal triclinic 4-bromobenzophenone polymorph was measured along axis b from 4.5 to 303K. The κ values versus temperature were represented as a sum of κ1, which generally describes the thermal conductivity of ordered crystals, and κTA responsible for activation processes, which fits nicely experimental data from 120 up. DFT analysis led to the conclusion that the activation agent responsible for the high-temperature behavior is the molecular mode that involves C–Br oscillations. It is for the first time that the exponential thermal conduction was ascribed to a specific intramolecular excitation.