Frequency-dependent shear viscosity, sound velocity, and sound attenuation near the critical point in liquids. II. Comparison with experiment

We compare the theoretical results of an explicit one loop calculation of the critical behavior of the sound propagation in pure liquids near the gas-liquid critical point, which has been derived within the field-theoretic renormalization group formalism, with experimental data in He-3, He-4, CO2, SF6, and Xe. The nonuniversal initial values of two dynamic model parameters, which are necessary for the calculation of all theoretical expressions, are determined by a fit of the shear viscosity at zero frequency in a small temperature region. The static quantities appearing in the theoretical expressions are taken from experiment. With these two dynamical initial values the temperature flow of the dynamic model parameters is completely determined. The sound attenuation and the sound velocity at arbitrary frequency as well as the thermal conductivity or the thermal diffusion coefficient may be calculated without any adjustable parameter. The parameter free predictions are in very good agreement with experimental results. This also holds for scaling plots of the reduced attenuation and dispersion taking into account the nonasymptotic behavior of the dynamic scale.