Scaled Particle Theory of Fluid Mixtures

An extension of a previous one-component theory of hard-sphere systems (in three, two, and one dimensions) and the surface tension of real systems is made to mixtures. The theory is based on consideration of an approximate expression for the work of adding an additional hard sphere to a mixture. Comparison between theory and molecular-dynamics calculations of the various contributions to the virial pressure (related to contact distribution functions) of such hard-sphere mixtures is excellent. Comparison of the theory with experimental surface tensions of mixtures of simple liquids is satisfactory.