PHASE-STABILITY LINES, SPINODALS AND DISTRIBUTION-FUNCTIONS FOR BINARY IMMISCIBLE MIXTURES

The phase-stability lines, the spinodals and the pair distribution fun ctions for simple binary immiscible mixtures obtained from perturbatio n theory are improved by using Guggenheim's quasichemical approximatio n. The stability lines are compared with Gibbs ensemble simulations fo r corresponding systems of coexisting bulk phases. The quasichemical a pproximation is found to lead to a quantitative agreement with the Gib bs ensemble data, for three-dimensional as well as two-dimensional sys tems, away from the critical regions. The analytical quasichemical cor rections to the pair distribution functions show a significant change in distribution, especially for the solute-solute particle distributio n. The results are used to characterize the phase growth.