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Performance of Density Functional Theory for Transition Metal Oxygen Bonds
Author(s) -
Moltved Klaus A.,
Kepp Kasper P.
Publication year - 2019
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201900862
Subject(s) - density functional theory , transition metal , chemistry , oxygen , chemical physics , computational chemistry , materials science , organic chemistry , catalysis
The accuracy of density functional theory (DFT) limits predictions in theoretical catalysis, and strong chemical bonds between transition metals and oxygen pose a particular challenge. We benchmarked 30 diverse density functionals against the bond dissociation enthalpies (BDE) of the 30 MO and 30 MO + diatomic systems of all the 3d, 4d, and 5d metals, to test universality across the d‐block as required in comparative studies. Seven functionals, B98, B97‐1, B3P86, B2PLYP, TPSSh, B3LYP, and B97‐2, display mean absolute errors (MAE) <30 kJ/mol. In contrast, many commonly used functionals such as PBE and RPBE overestimate M−O bonding by +30 kJ/mol and display MAEs from 48–76 kJ/mol. RPBE and OPBE reduce the over‐binding of PBE but remain very inaccurate. We identify a linear relationship (p‐value 7.6 ⋅ 10 −5 ) between the precision and accuracy of DFT, i. e. inaccurate functionals tend to produce larger, unpredictable random errors. Some functionals commonly deviate from this relationship: Thus, M06‐2X is very precise but not very accurate, whereas B3LYP* and MN15‐L are more accurate but less precise than M06‐2X. The best‐performing hybrids have 10–30 % HF exchange, but this can be relieved by double hybrids (B2PLYP). Most functionals describe trends well, but errors comparing 5d to 4d/3d are ∼10 kJ/mol larger than group‐wise errors, due to uncertainties in the spin‐orbit coupling corrections for effective core potentials, affecting e. g. Pt/Pd or Au/Ag comparisons.