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Updated: Aug 18, 2026

An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
The sound velocity in ideal liquid mixtures from thermal volume fluctuations
Helge Pfeiffer1, Karel Heremans
1Department of Chemistry, Katholieke Universiteit Leuven Celestijnenlaan 200D, 3001 Leuven, Belgium. helge.pfeiffer@fys.kuleuven.ac.be
Abstract:
The selection of the correct mixing rule for sound velocity in ideal liquid mixtures determines the interpretation of the sound velocity in real mixtures. This is especially important for the determination of apparent properties of solutes, such as their apparent compressibility. There are different approaches reported in the literature, and this article presents a new derivation of the mixing rule based on statistical mechanics. It is shown that the correlation of volume fluctuations between adjacent components has a crucial influence on the ideal mixing rule.
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