Critical Opalescence

Abstract

Intensity measurements of visible light and x‐rays and linewidth measurements of visible light scattered by one, two, and multicomponent systems for various equilibrium states in the neighborhood of the critical point are reviewed. By combining the angular dependence of the scattered intensity with that of the power spectrum from quasi‐elastic light scattering, one can determine separately the nature of the divergence of equilibrium properties, such as the isothermal compressibility and the osmotic coefficient; the transport coefficients, such as the thermal diffusivity and the diffusion coefficient; and the correlation range. Experimental data will be discussed in terms of the static and dynamic scaling hypothesis.