Light Scattering Arising from Composition Fluctuations in Multi-Component Systems

Abstract
A general theory of Rayleigh scattering due to composition fluctuations in multi‐component systems is developed with the aid of the grand canonical ensemble of Gibbs. It reduces to the usual expression for systems of two components, but contains previously neglected terms arising from thermodynamic interactions between solutes in systems of more than two components. The theory is used to interpret the turbidity measurements of polystyrene in benzene‐methanol mixtures of Ewart, Roe, Debye, and McCartney.