Asymmetry in Critical Light Scattering from Binary Mixtures of Phenol and Water in the Two-Phase Region

Previously reported experiments by Pusey, Bak, and Goldburg showed an asymmetry in the light scattering in the high- (h) and low- (l) density phases of critical mixtures of phenol and water at temperatures below the critical temperature Tc. Those experiments have been reanalyzed to evaluate the exponents τ and θ in the asymptotic expressions Iₕ₍ₗ₎∝(|t|^-γ±B^'|t|^-θ) and Γₕ₍ₗ₎∝(|t|^ν*∓B|τ|^τ), where I and Γ are, respectively, the intensity and spectral width of the scattered light and t=(T-Tc)Tc. The experimental results are discussed in terms of recent ideas concerning expected nonsymmetric behavior in pure fluids and binary mixtures. The value of τ the experiments yield can be accounted for in terms of simple linear dependence of the viscosity on concentration.