Assessment of the performance of tuned range-separated hybrid density functionals in predicting accurate quasiparticle spectra

Thomas Körzdörfer*, Robert M. Parrish, Noa Marom, John S. Sears, C. David Sherrill, Jean Luc Brédas

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

50 Scopus citations

Abstract

Long-range corrected hybrid functionals that employ a nonempirically tuned range-separation parameter have been demonstrated to yield accurate ionization potentials and fundamental gaps for a wide range of finite systems. Here, we address the question of whether this high level of accuracy is limited to the highest occupied/lowest unoccupied energy levels to which the range-separation parameter is tuned or whether it is retained for the entire valence spectrum. We examine several π-conjugated molecules and find that orbitals of a different character and symmetry require significantly different range-separation parameters and fractions of exact exchange. This imbalanced treatment of orbitals of a different nature biases the resulting eigenvalue spectra. Thus, the existing schemes for the tuning of range-separated hybrid functionals, while providing for good agreement between the highest occupied energy level and the first ionization potential, do not achieve accuracy comparable to reliable G 0W 0 computations for the entire quasiparticle spectrum.

Original languageEnglish (US)
Article number205110
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume86
Issue number20
DOIs
StatePublished - Nov 8 2012
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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