Berlin 2005 – scientific programme

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CPP: Chemische Physik und Polymerphysik

CPP 19: Dynamics I

CPP 19.2: Talk

Tuesday, March 8, 2005, 10:00–10:15, TU C230

Intrastack rotation in pyrene hexafluoroarsenate — •S. Matejcek and E. Dormann — Physikalisches Institut, Universität Karlsruhe (TH), D-76128 Karlsruhe, Germany

The specific heat of the quasi-one dimensional organic conductor pyrene hexafluoroarsenate ((Py)₇(Py)₄(AsF₆)₄·4CH₂Cl₂) was measured between 10 K and 250 K using the method of continuous heating. The contribution of the lattice to the specific heat was modelled using the Debye-model and Einstein terms. The variation of the specific heat at the structural phase transition that is accompanied by 60^∘ rotation of one of the stacked pyrene molecules could well be reproduced using a cooperation model including the formation of domains, and the surprisingly high transition entropy was explained qualitatively.