Correlation function near the critical mixing point of a binary liquid

Abstract

We have determined the order-parameter correlation function near the critical mixing point of 3-methylpentane-nitroethane by measuring the intensity of scattered light as a function of temperature. The data cover a range ${10}^{-6\mathrm{}}<t<\mathrm{}2.7\mathrm{}\times {10}^{-3\mathrm{}}$ in the reduced temperature $t=\frac{(T-T_c)}{T_c}$, which corresponds to a range $0.18<k\xi <25\mathrm{}$, where $k$ is the wave number and $\xi$ is the correlation length. The critical exponents deduced from the experimental data agree within combined errors with the values calculated theoretically for the Landau-Ginzburg-Wilson model. However, the data cannot be reconciled with the exponent values deduced from high-temperature series expansions for the three-dimensional Ising model.