Regensburg 2013 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 22: Statistical Physics (general)

DY 22.1: Vortrag

Mittwoch, 13. März 2013, 15:00–15:15, H48

Density fluctuations and self-diffusion along saturation in dense liquids: acoustic data and lattice model — Alexander Goncharov, Vyacheslav Melent'ev, and •Eugene Postnikov — Kursk State Univesity, Kursk, Russia

We consider the density fluctuations in fluids along a saturation line (both liquid and vapour phases) especially in the region closed to the malting point. Corresponding data are extracted from acoustic (speed of sound) and thermophysical (heat capacity ratio) measurements. The analysis of the dependence for reduced fluctuations (ratio of fluctuations of real media and ideal gas under the same PVT conditions) allow to determine the region of exponentially decaying dependencies, which is universal for a large amount of substances (liquid noble gases, chained hydrocarbons and their halogen substituted).

The considered theoretical lattice model (grand canonical statistic ensamble) argues that this region corresponds to absence of structure transitions but the presence of geometrical rearrangements of particles. The derived correspondence between these fluctuational characteristics and self-diffusion properties confirms the outlook about universality of universal scaling law for atomic distribution [Dzugutov, Nature, 381 (1996), 137] non only for simple (spherically symmetric) particles but for constituents of chained hydrocarbons as well.