2014/02/28 by Zeng-hui Yang, John R. Trail, Aurora Pribram−Jones +5 · 3 citations
Mathematics · Physics and Astronomy · #Advanced Chemical Physics Studies #Context (archaeology) #Degenerate energy levels #Density functional theory #Discontinuity (linguistics) #Eigenvalues and eigenvectors #Exact solutions in general relativity #Excited state #Geometry #Ground state #Kohn–Sham equations #Local-density approximation #Mathematical analysis #Mathematical physics #Mathematics #Physics #Quantum mechanics #Quantum, superfluid, helium dynamics #Spectroscopy and Quantum Chemical Studies #Symmetry (geometry) #cond-mat.mtrl-sci #physics.atom-ph #physics.chem-ph
paper · pdf · doi:10.1103/physreva.90.042501
published as Phys. Rev. A 90, 042501 (2014) · 9 pages, 13 figures
arxiv created 2014/09/01 · openalex publication_date 2014/10/02 · arxiv updated 2014/10/08 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We construct exact Kohn-Sham potentials for the ensemble density-functional theory (EDFT) from the ground and excited states of helium. The exchange-correlation (XC) potential is compared with the quasi-local-density approximation and both single-determinant and symmetry-eigenstate ghost-corrected exact exchange approximations. Symmetry-eigenstate Hartree exchange recovers distinctive features of the exact XC potential and is used to calculate the correlation potential. Unlike the exact case, excitation energies calculated from these approximations depend on ensemble weight, and it is shown that only the symmetry-eigenstate method produces an ensemble derivative discontinuity. Differences in asymptotic and near-ground-state behavior of exact and approximate XC potentials are discussed in the context of producing accurate optical gaps.