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Updated: May 15, 2026

An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
A light scattering study of non equilibrium fluctuations in liquid mixtures to measure the Soret and mass diffusion
F Croccolo1, H Bataller, F Scheffold
1Department of Physics, University of Fribourg, Ch. du Musée 3, CH-1700 Fribourg, Switzerland. fabrizio.croccolo@univ-pau.fr
Abstract:
We use dynamic near field scattering to measure the dynamics of concentration non equilibrium fluctuations at the steady-state of Soret separation. The analysis reveals that above a threshold wave vector q(c), the dynamics is governed by diffusion while at smaller wave vectors, gravity dominates. From the measurements, we extract both the mass diffusion and the Soret coefficients. Comparing our results with literature data, we find good agreement confirming that the proposed experimental technique can be considered a sound approach for the study of thermodiffusion processes.
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