DENSITY-FUNCTIONAL THEORY AS THERMODYNAMICS

Thermodynamical interpretation of the density functional theory is developed for an electronic ground state, with particular emphasis on the fact that when the system is not homogeneous the electronic kinetic energy varies from point to point. Local thermodynamical quantities, temperature, free energy, and entropy, are defined. The formalism yields the same Sackur-Tetrode expression for the local entropy earlier obtained by other methods, plus corrections of that equation for ''nonideality'. Various aspects of the thermodynamical description are discussed.