Noncovalent π•••π interaction between graphene and aromatic molecule: Structure, energy, and nature

Noncovalent pi center dot center dot center dot pi interactions between graphene and aromatic molecules have been studied by using density functional theory with empirical dispersion correction (omega B97X-D) combined with zeroth-order symmetry adapted perturbation theory (SAPT0). Excellent agreement of the interaction energies computed by means of omega B97X-D and spin component scaled (SCS) SAPT0 methods, respectively, shows great promise for the two methods in the study of the adsorption of aromatic molecules on graphene. The other important finding in this study is that, according to SCS-SAPT0 analyses, pi center dot center dot center dot pi interactions between graphene and aromatic molecules are largely dependent on both dispersion and electrostatic type interactions. It is also noticed that pi center dot center dot center dot pi interactions become stronger and more dispersive (less electrostatic) upon substitution of the very electronegative fluorine atoms onto the aromatic molecules. (C) 2014 AIP Publishing LLC.