Heat Capacities and Brillouin Scattering in Liquids

CHAPTER 7. Excess Volumes of Liquid Nonelectrolyte Mixtures

“…Within the constraints indicated above, v 0 may be treated as a thermodynamic equilibrium property. However, at higher frequencies many fluids show sound speed dispersion due to relaxation effects, 222,223,225,226 i.e. the experimental sound speed becomes larger than v 0 of Equation (7.66).…”

CHAPTER 1. Volumetric Properties: Introduction, Concepts and Selected Applications

“…83 For simple liquids (liquid noble gases), the ratio of the integrated intensity of the central, unshifted Rayleigh peak, I R , and the integrated intensity of the two Brillouin peaks, 2I B , is given by the LandauPlaczek ratio, i.e.…”

“…by directly measuring the volume increase on sudden decompression, this method is considerably less common and less accurate than that based on ultrasonics. 55,[78][79][80][81] For small sound wave amplitudes and sufficiently low frequencies well below any region where sound speed dispersion due to relaxation effects is observed, 82,83 to an excellent approximation v 2 0 ¼ @P @r…”

CHAPTER 12. Ultrasonics 1: Speed of Ultrasound, Isentropic Compressibility and Related Properties of Liquids

“…The net effect is to introduce a frequency-dependent volume viscosity 6 Z v (also known as bulk viscosity) with relaxation time t v . In nonassociated liquids, where translation-vibration relaxation is the dominant feature, it can be shown 1 that for a single relaxation process the corresponding dispersion of sound may be described by…”

“…6 For simple liquids (liquid noble gases), the ratio of the integrated intensity of the central, unshifted Rayleigh peak, I R , and the integrated intensity of the two Brillouin peaks, 2I B , is given by the Landau-Placzek ratio, i.e.…”