Comparison of Density-Functional Theory Dispersion Corrections for the DES15K Database

Abstract

While density-functional theory (DFT) remains one of the most widely used tools in computational chemistry, most functionals fail to properly account for the effects of London dispersion. Hence, there are many popular post-self-consistent methods to add a dispersion correction to the DFT energy. Until now, the most popular methods have never been compared on equal footing due to not being implemented in the same electronic structure packages. In this work, we performed a large-scale benchmarking study, directly comparing the accuracy of the exchange-hole dipole moment (XDM), D3BJ, D4, TS, MBD, and MBD-NL dispersion models when applied to the recent DES15K database of nearly 15,000 molecular complexes at both expanded and compressed geometries. Our study showed similarly good performance for all dispersion methods (except TS) when applied to neutral complexes. However, they all performed worse for ionic complexes, particularly those involving dications of alkaline earth metals, due to systematic overbinding by the base PBE0 density functional. Investigation of the largest outliers also revealed that only the MBD and MBD-NL methods demonstrate surprising errors for complexes involving alkali metal cations at compressed geometries where they tended to significantly overbind. As we would expect minimal dispersion binding for such complexes, we further investigated the origins of these errors for the potential energy curve of a model cation−π complex. Overall, there is little choice between the XDM, D3BJ, D4, MBD, and MBD-NL dispersion methods for most systems. However, the MBD-based methods are not recommended for complexes involving organic species and alkali or alkaline earth metal cations, for example when modeling Li + intercalation into graphite.

Axial–equatorial equilibrium in substituted cyclohexanes: a DFT perspective on a small but complex problem

“…Such limited variations in going from the D3(BJ) to the D4 correction for functionals of the PBE family was already reported in literature. 80,81…”

Nitrile Imines as Peptide and Oligonucleotide Photo-Cross-Linkers in Gas-Phase Ions

“…Two hundred snapshots of each trajectory were taken at regular intervals and fully gradient-optimized with PM6-D3H4. The resulting structures were compacted by removing duplicates and submitted to gradient geometry optimization with B3LYP that was augmented by empirical dispersion terms with Becke–Johnson damping (GD3-BJ) . B3LYP-GD3-BJ was also used to calculate harmonic frequencies.…”

“…The resulting structures were compacted by removing duplicates and submitted to gradient geometry optimization with B3LYP 43 that was augmented by empirical dispersion terms 44 with Becke−Johnson damping (GD3-BJ). 45 B3LYP-GD3-BJ was also used to calculate harmonic frequencies. Additional sets of optimized geometries were obtained by M06-2X calculations 46 with the 6-31+G(d,p) basis set that were also used for single-point energy calculations with M06-2X/6-311++G(2d,p).…”

Reliable Dimerization Energies for Modeling of Supramolecular Junctions

“…In the present work, the domain-based local pair natural orbital (DLPNO) scheme [ 29 , 30 , 31 ] was used together with an iterative treatment of triple excitations within the CCSD(T) method [ 32 ] to establish a level of absolute accuracy of the resulting scheme, abbreviated as DLPNO-CCSD(T). Other computational methods considered here are part of the large family of dispersion-corrected density-functional theory (DC DFT) approaches [ 33 , 34 , 35 ]. Specifically, the ωB97X-3c/vDZP strategy, most recently proposed by Grimme et al (see reference [ 34 ] and Section 4 ), was tested, and its results were put into perspective by comparing them to those obtained from two well-established but computationally much more demanding DC DFT methods: B3LYP-D3 and B2PLYP-D3(BJ); these were applied together with an ample basis set (see Section 4 for the specifications).…”