Evidence for an Intrinsic Refractive-Index Anomaly in a Critical Binary Liquid Mixture

Abstract
New experimental data for the refractive-index behavior in the homogeneous phase below the lower critical solution point in critical-composition liquid mixtures of triethylamine and water are presented. From a comparison with existing density data it is concluded that the critical anomaly in the refractive index includes an intrinsic effect opposite in sign to the density contribution.