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Excitation energies in density functional theory: An evaluation and a diagnostic test

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Excitation energies in density functional theory: An evaluation and a diagnostic test. / Peach, Michael J. G.; Benfield, Peter; Helgaker, Trygve; Tozer, David J.

In: Journal of Chemical Physics, Vol. 128, No. 4, ARTN 044118, 28.01.2008.

Research output: Contribution to journalJournal articlepeer-review

Harvard

Peach, MJG, Benfield, P, Helgaker, T & Tozer, DJ 2008, 'Excitation energies in density functional theory: An evaluation and a diagnostic test', Journal of Chemical Physics, vol. 128, no. 4, ARTN 044118. https://doi.org/10.1063/1.2831900

APA

Peach, M. J. G., Benfield, P., Helgaker, T., & Tozer, D. J. (2008). Excitation energies in density functional theory: An evaluation and a diagnostic test. Journal of Chemical Physics, 128(4), [ARTN 044118]. https://doi.org/10.1063/1.2831900

Vancouver

Peach MJG, Benfield P, Helgaker T, Tozer DJ. Excitation energies in density functional theory: An evaluation and a diagnostic test. Journal of Chemical Physics. 2008 Jan 28;128(4). ARTN 044118. https://doi.org/10.1063/1.2831900

Author

Peach, Michael J. G. ; Benfield, Peter ; Helgaker, Trygve ; Tozer, David J. / Excitation energies in density functional theory: An evaluation and a diagnostic test. In: Journal of Chemical Physics. 2008 ; Vol. 128, No. 4.

Bibtex

@article{1a295881787541f99fb6524a2b6cacfa,
title = "Excitation energies in density functional theory: An evaluation and a diagnostic test",
abstract = "Electronic excitation energies are determined using the CAM-B3LYP Coulomb-attenuated functional [T. Yanai Chem. Phys. Lett. 393, 51 (2004)], together with a standard generalized gradient approximation (GGA) and hybrid functional. The degree of spatial overlap between the occupied and virtual orbitals involved in an excitation is measured using a quantity Lambda, and the extent to which excitation energy errors correlate with Lambda is quantified. For a set of 59 excitations of local, Rydberg, and intramolecular charge-transfer character in 18 theoretically challenging main-group molecules, CAM-B3LYP provides by far the best overall performance; no correlation is observed between excitation energy errors and Lambda, reflecting the good quality, balanced description of all three categories of excitation. By contrast, a clear correlation is observed for the GGA and, to a lesser extent, the hybrid functional, allowing a simple diagnostic test to be proposed for judging the reliability of a general excitation from these functionals-when Lambda falls below a prescribed threshold, excitations are likely to be in very significant error. The study highlights the ambiguous nature of the term {"}charge transfer,{"} providing insight into the observation that while many charge-transfer excitations are poorly described by GGA and hybrid functionals, others are accurately reproduced. (C) 2008 American Institute of Physics.",
keywords = "2ND-ORDER PERTURBATION-THEORY, CORRELATED MOLECULAR CALCULATIONS, ABSORPTION-SPECTRA, TRANSFER EXCITED-STATES, GAUSSIAN-BASIS SETS, ELECTRONIC EXCITATIONS, RANGE CHARGE-TRANSFER, AB-INITIO, ASYMPTOTICALLY CORRECTED POTENTIALS, COUPLED-CLUSTER",
author = "Peach, {Michael J. G.} and Peter Benfield and Trygve Helgaker and Tozer, {David J.}",
year = "2008",
month = jan,
day = "28",
doi = "10.1063/1.2831900",
language = "English",
volume = "128",
journal = "Journal of Chemical Physics",
issn = "0021-9606",
publisher = "AMER INST PHYSICS",
number = "4",

}

RIS

TY - JOUR

T1 - Excitation energies in density functional theory: An evaluation and a diagnostic test

AU - Peach, Michael J. G.

AU - Benfield, Peter

AU - Helgaker, Trygve

AU - Tozer, David J.

PY - 2008/1/28

Y1 - 2008/1/28

N2 - Electronic excitation energies are determined using the CAM-B3LYP Coulomb-attenuated functional [T. Yanai Chem. Phys. Lett. 393, 51 (2004)], together with a standard generalized gradient approximation (GGA) and hybrid functional. The degree of spatial overlap between the occupied and virtual orbitals involved in an excitation is measured using a quantity Lambda, and the extent to which excitation energy errors correlate with Lambda is quantified. For a set of 59 excitations of local, Rydberg, and intramolecular charge-transfer character in 18 theoretically challenging main-group molecules, CAM-B3LYP provides by far the best overall performance; no correlation is observed between excitation energy errors and Lambda, reflecting the good quality, balanced description of all three categories of excitation. By contrast, a clear correlation is observed for the GGA and, to a lesser extent, the hybrid functional, allowing a simple diagnostic test to be proposed for judging the reliability of a general excitation from these functionals-when Lambda falls below a prescribed threshold, excitations are likely to be in very significant error. The study highlights the ambiguous nature of the term "charge transfer," providing insight into the observation that while many charge-transfer excitations are poorly described by GGA and hybrid functionals, others are accurately reproduced. (C) 2008 American Institute of Physics.

AB - Electronic excitation energies are determined using the CAM-B3LYP Coulomb-attenuated functional [T. Yanai Chem. Phys. Lett. 393, 51 (2004)], together with a standard generalized gradient approximation (GGA) and hybrid functional. The degree of spatial overlap between the occupied and virtual orbitals involved in an excitation is measured using a quantity Lambda, and the extent to which excitation energy errors correlate with Lambda is quantified. For a set of 59 excitations of local, Rydberg, and intramolecular charge-transfer character in 18 theoretically challenging main-group molecules, CAM-B3LYP provides by far the best overall performance; no correlation is observed between excitation energy errors and Lambda, reflecting the good quality, balanced description of all three categories of excitation. By contrast, a clear correlation is observed for the GGA and, to a lesser extent, the hybrid functional, allowing a simple diagnostic test to be proposed for judging the reliability of a general excitation from these functionals-when Lambda falls below a prescribed threshold, excitations are likely to be in very significant error. The study highlights the ambiguous nature of the term "charge transfer," providing insight into the observation that while many charge-transfer excitations are poorly described by GGA and hybrid functionals, others are accurately reproduced. (C) 2008 American Institute of Physics.

KW - 2ND-ORDER PERTURBATION-THEORY

KW - CORRELATED MOLECULAR CALCULATIONS

KW - ABSORPTION-SPECTRA

KW - TRANSFER EXCITED-STATES

KW - GAUSSIAN-BASIS SETS

KW - ELECTRONIC EXCITATIONS

KW - RANGE CHARGE-TRANSFER

KW - AB-INITIO

KW - ASYMPTOTICALLY CORRECTED POTENTIALS

KW - COUPLED-CLUSTER

UR - http://www.scopus.com/inward/record.url?scp=38849133661&partnerID=8YFLogxK

U2 - 10.1063/1.2831900

DO - 10.1063/1.2831900

M3 - Journal article

VL - 128

JO - Journal of Chemical Physics

JF - Journal of Chemical Physics

SN - 0021-9606

IS - 4

M1 - ARTN 044118

ER -