Global phase diagram for a spin-3/2 Ising model of ternary fluid mixtures

Recently, we introduced a lattice-gas model of a ternary fluid mixture, and located a nonsymmetric tricritical point within the mean-field approximation. Here, we present the global phase diagram in the four-dimensional space composed of temperature ($T$) and the chemical potentials (${\mu }_1,{\mu }_2,{\mu }_3$) corresponding to the three types of constituent molecules. We believe many features of the model phase diagram have quite general validity, and experimental testing of our predictions is suggested. Our results are consistent with Gibbs phase rule, but they go beyond it, by predicting the number of critical and coexistence surfaces of a given order, and their connectivity properties.