Quantum chemical exploration of dimeric forms of polycyclic aromatic hydrocarbons, naphthalene, perylene, and coronene

We have found dimeric forms of polycyclic aromatic hydrocarbon (di-PAH) molecules by quantum chemical calculations. Geometry optimization starting from short distances of ca. 0.15 nm between two PAH molecules placed in parallel gave cage structures of di-PAH with CC bond connections forming four-membered rings between the PAH molecules. The di-PAH molecules are located in sufficiently deep potential energy wells surrounded by high energy barriers, although their energies are much higher than those of the isolated two PAH molecules