A (Nearly) Universally Applicable Method for Modeling Noncovalent Interactions Using B3LYP.

B3LYP is the most widely used density-functional theory (DFT) approach because it is capable of accurately predicting molecular structures and other properties. However, B3LYP is not able to reliably model systems in which noncovalent interactions are important. Here we present a method that corrects this deficiency in B3LYP by using dispersion-correcting potentials (DCPs). DCPs are utilized by simple modifications to input files and can be used in any computational package that can read effective-core potentials. Therefore, the technique requires no programming. DCPs (developed for H, C, N, and O) produce the best results when used in conjunction with 6-31+G(2d,2p) basis sets. The B3LYP-DCP approach was tested on the S66, S22, and HSG-A benchmark sets of noncovalently interacting dimers and trimers and was found to, on average, significantly outperform almost all other DFT-based methods that were designed to treat van der Waals interactions. Users of B3LYP who wish to model systems in which noncovalent interactions (viz., steric repulsion, hydrogen bonding, π-stacking) are present, should consider B3LYP-DCP.