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Updated: May 23, 2026

An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
The dispersive behavior of collective excitations in fluids: an experimental test for the generalized collective
1Sincrotrone Trieste, S.S. 14 km 163,5 in AREA Science Park 34012 Basovizza, Trieste, Italy.
Abstract:
The predictions of the generalized collective modes (GCM) theory on the non-hydrodynamic dispersion of collective excitations of liquids and supercritical fluids have been tested against previous inelastic x-ray scattering measurements on samples of increasing complexity. We observed a good agreement between experimental results and theoretical predictions within the hypothesis that sound propagation is adiabatic. Overall, the performed comparison provides an experimental validation of GCM predictions and shows that, even in the transition region between the hydrodynamic and the mesoscopic regimes, thermal fluctuations have a minor influence on the dispersion, whose non-hydrodynamic effects are mostly driven by viscoelastic phenomena.
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