Benchmark calculations of the adsorption of aromatic molecules on graphene

Selecting the saturated graphene fragment as a model of graphene, we have investigated seven popular density functionals, including B97X-D, B97-D, B-LYP-D3, M05-2X, M06-2X, M11-L, and N12, for their performance in describing the adsorption of aromatic molecules on graphene. The best performing functionals are B97-D, B-LYP-D3, and B97X-D. M05-2X, M06-2X, and M11-L significantly underestimate the adsorption strengths, while N12 fails completely in this respect. The effects of the basis sets and size of the saturated graphene fragments on the geometries, energies, and properties for the adsorption of aromatic molecules on graphene have also been studied. It was found that the small basis sets such as 6-31G(d) and jun-cc-pVDZ are not suitable for the accurate description of the adsorption of aromatic molecules on graphene. The size of selected graphene fragments has a little effect on both the B97X-D and SCS-SAPT0 interaction energies, but the effects of the size of selected graphene fragments on the energy components are significant in some cases of the adsorption of aromatic molecules on graphene. The surprising weakness of electrostatic interactions by F substitution for the adsorption of F-substituted benzenes on graphene was explained using the energy component analysis. (c) 2015 Wiley Periodicals, Inc.