XX.—On the Theory of Binary Fluid Mixtures

Abstract

A number of analogues to the simple fluid compressibility equation are deduced by considering fluctuations in a binary mixture; and their simplest expressions are found to be in terms of the binary mixture direct correlation functions. The accuracy of these results is tested with the aid of the appropriate extension of the approximate Born-Green theory, which facilitates the demonstration of consistency with the first three terms of the virial expansion. The problem of the evaluation of the corresponding radial distribution functions by means of X-ray or optical scattering is taken as far as the determination, in principle, of a concentration correlation function from observations of critical opalescence.