Abstract
Gould and Pittalis [Phys. Rev. Lett. 123, 016401 (2019)] recently revealed a density-driven (DD) correlation energy that is specific to many-electron ensembles and must be accounted for by approximations. We derive in this Letter a general and simpler expression in terms of the ensemble weights, the ensemble Kohn-Sham (KS) orbitals, and their linear response to variations in the ensemble weights. As no additional state-driven KS systems are needed, its evaluation is greatly simplified. We confirm the importance of DD effects and introduce a direct and promising route to approximations.
Reference
Emmanuel Fromager
Individual Correlations in Ensemble Density Functional Theory: State- and Density-Driven Decompositions without Additional Kohn-Sham Systems
Phys. Rev. Lett. 124, 243001 – Published 19 June 2020, DOI : 10.1103/PhysRevLett.124.243001
Contact chercheur
Emmanuel Fromager, équipe LCQS, Institut de Chimie (UMR 7177).
