Generalized Lattice Model of Multi-Component Systems with Internal Degrees of Freedom. I. General consideration

The paper contains the generalization of usual lattice model of multicomponent systems. The generalization is related to account the following factors: 1. The short-range parts of interatomic repulsions. These repulsions are not identical for different pairs of atoms, therefore it is impossible to take into account the repulsions by means of usual ideal lattice introduction. 2. The long-range interatomic potentials take into account by means of effective fields approximation. 3. The presence the interatomic potentials depending on some inner degrees of freedoms such as atomic electric and/or magnetic momentum. The Helmholtz free energy functional in the generalized lattice model is reduced to the Ginzburg-Landau-Cahn-Hilliard-like (GLCH) form. The connection between the interatomic potentials characteristics and the parameters of the GLCH-like functional is obtained. The equations for both full and partial equilibrium distributions of the species in multicomponent systems are derived.