Degenerate ground states and a fractional number of electrons in density and reduced density matrix functional theory


Journal Article

For a linear combination of electron densities of degenerate ground states, it is shown that the value of any energy functional is the ground state energy, if the energy functional is exact for ground state densities, size consistent, and translational invariant. The corresponding functional of kinetic and interaction energy is the linear combination of the functionals of the degenerate densities. Without invoking ensembles, it is shown that the energy functional of fractional number electrons is a series of straight lines interpolating its values at integers. These results underscore the importance of grand canonical ensemble formulation in density functional theory.

Full Text

Duke Authors

Cited Authors

  • Yang, W; Zhang, Y; Ayers, PW

Published Date

  • May 2000

Published In

Volume / Issue

  • 84 / 22

Start / End Page

  • 5172 - 5175

PubMed ID

  • 10990895

Pubmed Central ID

  • 10990895

Electronic International Standard Serial Number (EISSN)

  • 1079-7114

International Standard Serial Number (ISSN)

  • 0031-9007

Digital Object Identifier (DOI)

  • 10.1103/physrevlett.84.5172


  • eng