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 $T_c$. Those experiments have been reanalyzed to evaluate the exponents $\tau$ and $\theta$ in the asymptotic expressions $I_{h\left(l\right)\mathrm{}}\propto ({\mathrm{}\left|t\right|\mathrm{}}^{-\gamma }\pm B^{\prime }{\mathrm{}\left|t\right|\mathrm{}}^{-\theta })$ and ${\Gamma }_{h\left(l\right)\mathrm{}}\propto ({\mathrm{}\left|t\right|\mathrm{}}^{{\nu }^{*}}\mp B{\left|\tau \right|}^{\tau })$, where $I$ and $\Gamma$ are, respectively, the intensity and spectral width of the scattered light and $t=\frac{(T-T_c)}{T_c}$. The experimental results are discussed in terms of recent ideas concerning expected nonsymmetric behavior in pure fluids and binary mixtures. The value of $\tau$ the experiments yield can be accounted for in terms of simple linear dependence of the viscosity on concentration.