Correlation function near the critical mixing point of a binary liquid

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<t<2.7×10^-3 in the reduced temperature t=(T-Tc)Tc, which corresponds to a range 0.18<kξ<25, where k is the wave number and ξ 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.