External field as the functional of inhomogeneous density and the density matrix functional approach
Joint Institute for High Temperatures, Russian Academy of Sciences - Izhorskaia St., 13, Bd. 2. Moscow 125412, Russia
2 Eindhoven University of Technology - P.O. Box 513, MB 5600 Eindhoven, The Netherlands, EU
3 State Academy of Transport Communications - Moscow, Russia
Accepted: 14 May 2012
Based on the Hohenberg-Kohn lemma and the hypotheses of the density functional existence for the external-field potential, it is shown that the strict result of the density functional theory is the equation of the external-field potential as the density functional. This result leads to the impossibility of determining the inhomogeneous density in a given external field if the inhomogeneous density is not known a priori. The problem encountered is intimately associated with the absence of a regular procedure for determining the universal density functional. The result obtained shows the advantage of the density matrix functional theory which yields a correct description of the inhomogeneous electron system in both the ideal-gas approximation and the self-consistent Hartree-Fock approximation in contrast to the density functional theory.
PACS: 31.15.E- – Density-functional theory / 71.15.Mb – Density functional theory, local density approximation, gradient and other corrections / 52.25.-b – Plasma properties
© EPLA, 2012