The M06 suite of density functionals for main group thermochemistry, thermochemical kinetics, noncovalent interactions, excited states, and transition elements: two new functionals and systematic testing of four M06-class functionals and 12 other functionals

Abstract

We present two new hybrid meta exchangecorrelation functionals, called M06 and M06-2X. The M06 functional is parametrized including both transition metals and nonmetals, whereas the M06-2X functional is a highnonlocality functional with double the amount of nonlocal exchange (2X), and it is parametrized only for nonmetals.The functionals, along with the previously published M06-L local functional and the M06-HF full-Hartree-Fock functionals, constitute the M06 suite of complementary functionals. We assess these four functionals by comparing their performance to that of 12 other functionals and Hartree-Fock theory for 403 energetic data in 29 diverse databases, including ten databases for thermochemistry, four databases for kinetics, eight databases for noncovalent interactions, three databases for transition metal bonding, one database for metal atom excitation energies, and three databases for molecular excitation energies. We also illustrate the performance of these 17 methods for three databases containing 40 bond lengths and for databases containing 38 vibrational frequencies and 15 vibrational zero point energies. We recommend the M06-2X functional for applications involving main-group thermochemistry, kinetics, noncovalent interactions, and electronic excitation energies to valence and Rydberg states. We recommend the M06 functional for application in organometallic Contribution to the Mark S. Gordon 65th Birthday Festschrift Issue.

How Method-Dependent Are Calculated Differences between Vertical, Adiabatic, and 0–0 Excitation Energies?

“…In contrast, the ab As for the statistical analyses in Table 2 Third, the least accurate functional for the current benchmark set is M06-HF (MAE of 0.50 eV), despite that this method has a wider range of applicability to different types of excited states (including Rydberg and charge-transfer states) than most other functionals. 10,69 Since the majority of the 96 states have valence character, this finding corroborates the observation made in a recent ΔE ve -based benchmark that M06-HF is not very well suited for valence excitations. 15 In this regard, it is of course possible that the M06-HF results are negatively affected by the procedure that all calculations required to obtain ΔE 00 energies with a given method are carried out using that particular method, including not only the singlepoint calculations but also the geometry optimizations and frequency calculations.…”

Oxygen Atom Transfer and Oxidative Water Incorporation in Cuboidal Mn3MOn Complexes Based on Synthetic, Isotopic Labeling, and Computational Studies

“…First we compared the accuracy of using the B3LYP and M06 [7] methodologies by benchmarking a single-electron redox potential in simple well characterized early transition metal (TM) complexes. We compare to experimental values and previous QM values in Table S1.…”

Enzyme Promiscuity in Enolase Superfamily. Theoretical Study of o-Succinylbenzoate Synthase Using QM/MM Methods

“…[48][49][50] In equation 1, HL stands for the high level chosen to obtain the corrected estimation of the activation free energy. In our case M06-2X/6-31+G(d,p) 34,35 has been used. HL calculations are carried out under the effect of the field created by the MM environment, where the electrostatic coupling between the QM and MM subsystems is calculated using point charges on the QM atoms.…”

“…This method has been successfully used to determine the energetics associated to chemical reactions. 34,35 The…”