Dresden 2011 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 38: Poster: Colloids and Complex Liquids

CPP 38.27: Poster

Mittwoch, 16. März 2011, 17:00–19:00, P2

The isotope Soret effect in molecular liquids: a quantum effect at room temperatures — •Steffen Hartmann¹, Konstantin Morozov², Zina Slimane¹, and Werner Köhler¹ — ¹Physikalisches Institut, Universität Bayreuth — ²Department of Chemical Engineering, Technion - Israel Institute of Technology, Haifa

In a multicomponent system, a temperature gradient induces a diffusive mass flow, which is counterbalanced in the stationary state by Fickian mass diffusion. The occuring concentration gradient can be described by the Soret coefficient, which can be split into additive contributions. We have developed a theory for the so-called isotopic contribution to the Soret effect of binary liquid mixtures based on the contribution of librational and vibrational motions to the partial pressure. Contrary to its name, the isotopic contribution is not limited to purely isotopic substitution but can be dominating or even sole effect in mixtures of different but chemically similar molecules. To test the theory, we have performed experiments for the binary mixtures from the homologous series of the halobenzenes and for halobenzenes in toluene and cyclohexane, respectively.