Interactions of graphene sheets deduced from properties of polycyclic aromatic hydrocarbons

Intermolecular interactions of coronene dimer were studied with symmetry-adapted perturbation theory based on the density functional theory description of the monomers [SAPT(DFT)]. The most stable stacked structure was found to have the interaction energy of -17.45 kcal/mol, slightly lower than the structure analogous to graphite (-17.36 kcal/mol). The latter energy was extrapolated to the interaction energy of two graphene sheets. The effects of interactions of multiple layers were also estimated leading to the exfoliation energy of graphite equal to 45.3 meV per carbon atom. The SAPT(DFT)-based decomposition into physical quantities of the interaction energies shows the dominant effect of the dispersion interactions with a weaker electrostatic contribution due to penetration effects. The extrapolated physical picture of the graphene-graphene interaction is very similar to that of smaller stacked polycyclic aromatic hydrocarbons.