Abstract
An electron density distribution which can be represented by that of a single-determinant ground state of noninteracting electrons in an external potential is called pure-state -representable (P-VR). Most physical electronic systems are P-VR. Systems which require a weighted sum of several such determinants to represent their density are called ensemble -representable (E-VR). This paper develops formal Kohn-Sham equations for E-VR physical systems, using the appropriate coupling constant integration. It also derives local density- and generalized gradient approximations, and conditions and corrections specific to ensembles.
- Received 5 December 2000
DOI:https://doi.org/10.1103/PhysRevLett.87.093001
©2001 American Physical Society