Journal article
Biased Spin-State Energetics of Fe(II) Molecular Complexes within Density-Functional Theory and the Linear-Response Hubbard U Correction
Journal of chemical theory and computation, Vol.16(11), pp.6755-6762
11/10/2020
DOI: 10.1021/acs.jctc.0c00628
PMID: 33108722
Abstract
The spin-state energetics of six Fe(II) molecular complexes are computed using the linear-response Hubbard U approach within DFT. The adiabatic energy differences, Delta EH-L, between the high-spin (S = 2) and the low-spin (S = 0) states are computed and compared with accurate-coupled cluster-corrected CASPT2 results. We show that DFT+U fails in correctly capturing the ground state for strong-field ligands yielding Delta EH-L that are almost constant throughout the molecular series. This bias toward high spin together with the metal/ligand charge transfer upon U correction are here quantified and explained using molecular orbital diagrams involving both sigma- and pi-bonding interactions. With increasing ligand-field strengths this bias also increases owing to the stronger molecular character of the metal/ligand Kohn-Sham orbitals thus resulting in large deviations from the reference larger than 4 eV. Smaller values of U can be employed to mitigate this effect and recover the right energetics.
Details
- Title: Subtitle
- Biased Spin-State Energetics of Fe(II) Molecular Complexes within Density-Functional Theory and the Linear-Response Hubbard U Correction
- Creators
- Lorenzo A. Mariano - Institut polytechnique de GrenobleBess Vlaisavljevich - University of South DakotaRoberta Poloni - Institut polytechnique de Grenoble
- Resource Type
- Journal article
- Publication Details
- Journal of chemical theory and computation, Vol.16(11), pp.6755-6762
- DOI
- 10.1021/acs.jctc.0c00628
- PMID
- 33108722
- NLM abbreviation
- J Chem Theory Comput
- ISSN
- 1549-9618
- eISSN
- 1549-9626
- Publisher
- Amer Chemical Soc
- Number of pages
- 8
- Grant note
- ANR-15-CE06-0003-01 / French National Agency for Research; Agence Nationale de la Recherche (ANR) A0020907211 / GENCI under the CINES DE-SC0019463 / Department of Energy, Basic Energy Sciences; United States Department of Energy (DOE) DE-AC02-05CH11231 / National Energy Research Scientific Computing Center (NERSC), a U.S. Department of Energy Office of Science User Facility 1626516 / NSF; National Science Foundation (NSF)
- Language
- English
- Date published
- 11/10/2020
- Academic Unit
- Chemistry
- Record Identifier
- 9984618511102771
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