Singlet-triplet energy gaps for diradicals from fractional-spin density-functional theory

Journal Article

Open-shell singlet diradicals are difficult to model accurately within conventional Kohn-Sham (KS) density-functional theory (DFT). These methods are hampered by spin contamination because the KS determinant wave function is neither a pure spin state nor an eigenfunction of the S2 operator. Here we present a theoretical foray for using single-reference closed-shell ground states to describe diradicals by fractional-spin DFT (FS-DFT). This approach allows direct, self-consistent calculation of electronic properties using the electron density corresponding to the proper spin eigenfunction. The resulting FS-DFT approach is benchmarked against diradical singlet-triplet gaps for atoms and small molecules. We have also applied FS-DFT to the singlet-triplet gaps of hydrocarbon polyacenes. © 2010 American Chemical Society.

Full Text

Duke Authors

Cited Authors

  • Ess, DH; Johnson, ER; Hu, X; Yang, W

Published Date

  • 2011

Published In

Volume / Issue

  • 115 / 1

Start / End Page

  • 76 - 83

PubMed ID

  • 21141988

International Standard Serial Number (ISSN)

  • 1089-5639

Digital Object Identifier (DOI)

  • 10.1021/jp109280y