Exchange correlation energy as a function of the orbital occupancies: Implementation on first principles local orbital methods

Abstract

AbstractWe introduce a local density formalism, where the total energy of the system is obtained as a function of the orbital occupancies {nμσ}. The exchange energy, EX is written in terms of the electrostatic interaction between a charge nμσ and its hole (1 − nμσ), while the correlation energy is analyzed by means of a Hubbard Hamiltonian using a dynamic field approximation. Once the exchange correlation energy is obtained as an explicit function of the {nμσ}, our orbital occupancy method is completely defined. Our approach is then applied to bulk diamond, Si, and zinc‐blende GaN, as well as the benzene molecule. The results obtained show that this approach offers an interesting alternative to the well‐established density functional theory methods based on the electron density ρ($\vec{r}$ ). © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2003