Method of Many-Particle Density Functionals for Description of Two-Component System

The possibility of applying the density functional method to the systems consisting of two subsystems that include fermions of different signs is studied. While describing similar systems, in particular molecules and nanoclusters, the density functional method is used on assumption that system properties can be described with consideration of the basic state of the inhomogeneous electron gas that moves under condition of potential created by the immobile atomic nuclei. It is shown that this approach leads to the error in determination of the system's basic energy, and methods of quantitative estimation of this error are indicated. The scale relations are investigated which occur in systems that include particles of two types.