Description of core excitations by time-dependent density functional theory with local density approximation, generalized gradient approximation, meta-generalized gradient approximation, and hybrid functionals

Yutaka Imamura, Takao Otsuka, Hiromi Nakai

Research output: Contribution to journalArticle

30 Citations (Scopus)

Abstract

Time-dependent density functional theory (TDDFT) is employed to investigate exchange-correlation-functional dependence of the vertical core-excitation energies of several molecules including H, C, N, O, and F atoms. For the local density approximation (LDA), generalized gradient approximation (GGA), and meta-GGA, the calculated Xls-π* excitation energies (X = C, N, O, and F) are severely underestimated by more than 13 eV. On the other hand, time-dependent Hartree-Fock (TDHF) overestimates the excitation energies by more than 6 eV. The hybrid functionals perform better than pure TDDFT because HF exchange remedies the underestimation of pure TDDFT. Among these hybrid functionals, the Becke-Half-and-Half-Lee-Yang-Parr (BHHLYP) functional including 50% HF exchange provides the smallest error for core excitations. We have also discovered the systematic trend that the deviations of TDHF and TDDFT with the LDA, GGA, and meta-GGA functionals show a strong atomdependence. Namely, their deviations become larger for heavier atoms, while the hybrid functionals are significantly less atom-dependent.

Original languageEnglish
Pages (from-to)2067-2074
Number of pages8
JournalJournal of Computational Chemistry
Volume28
Issue number12
DOIs
Publication statusPublished - 2007 Sep 1

Keywords

  • Atom-dependence
  • Core excitations
  • Functional-dependence
  • Time-dependent density functional theory

ASJC Scopus subject areas

  • Chemistry(all)
  • Computational Mathematics

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