Accurate dispersion interactions from standard density-functional theory methods with small basis setsElectronic supplementary information (ESI) available: Full tables: Fig. S1. Sample Gaussian-03 input file demonstrating the use of DCPs with B971/6-31G(d) and counterpoise corrections, for calculation of the methane dimer binding energy. Table S2. Binding Energies for the set of non-covalently bound dimers. Comparison of Method/Basis-DCP and M06-2X/6-31G(d) to high-level ab initio data. Table S3

• Main Authors: Mackie, Iain D, DiLabio, Gino A
• Format: Article
• Language: English
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/b919152f

B971, PBE and PBE1 density functionals with 6-31G(d) basis sets are shown to accurately describe the binding in dispersion bound dimers. This is achieved through the use of dispersion-correcting potentials (DCPs) in conjunction with counterpoise corrections. DCPs resemble and are applied like conventional effective core potentials that can be used with most computational chemistry programs without code modification. Rather, DCPs are implemented by simple appendage to the input files for these types of programs. Binding energies are predicted to within ca. 11% and monomer separations to within ca. 0.06 Å of high-level wavefunction data using B971/6-31G(d)-DCP. Similar results are obtained for PBE and PBE1 with the 6-31G(d) basis sets and DCPs. Although results found using the 3-21G(d) are not as impressive, they never-the-less show promise as a means of initial study for a wide variety of dimers, including those dominated by dispersion, hydrogen-bonding and a mixture of interactions. Notable improvement is found in comparison to M06-2X/6-31G(d) data, e.g. , mean absolute deviations for the S22-set of dimers of ca. 13.6 and 16.5% for B971/6-31G(d)-DCP and M06-2X, respectively. However, it should be pointed out that the latter data were obtained using a larger integration grid size since a smaller grid results in different binding energies and geometries for simple dispersion-bound dimers such as methane and ethene. Dispersion-correcting potentials developed for B971, PBE and PBE1 allow for the accurate description of non-covalent interactions using 6-31G(d) basis sets.