Unified formulation of fundamental and optical gap problems in density-functional theory for ensembles
Chemical Physics
2018-08-29 v4 Strongly Correlated Electrons
Abstract
Solving the fundamental and optical gap problems, which yield information about charged and neutral excitations in electronic systems, is one of the biggest challenge in density-functional theory (DFT). Despite their intrinsic difference, we show that the two problems can be made formally identical by introducing a universal and canonical ensemble weight dependent exchange-correlation (xc) density functional. The weight dependence of the xc energy turns out to be the key ingredient for describing the infamous derivative discontinuity and represents a new path for its approximation.
Keywords
Cite
@article{arxiv.1805.08715,
title = {Unified formulation of fundamental and optical gap problems in density-functional theory for ensembles},
author = {Bruno Senjean and Emmanuel Fromager},
journal= {arXiv preprint arXiv:1805.08715},
year = {2018}
}