Analyzing Interaction Energy of Polycyclic Aromatic Hydrocarbons (PAH) Dimers

Abstract

The potential energy surfaces of several dimer configurations of polycyclic aromatic hydrocarbons (e.g., naphthalene and anthracene) have been investigated. The calculations have been carried out using both force field and quantum mechanical methods, in particular Hartree Fock (HF-D3) and Density Functional B97d-D3 approaches, which include dispersion corrections in both cases. The quantum mechanical methods give rise to very similar potential energy surfaces with pronounced minimum structures, which are not reproduced with force field methods. The Morokuma decomposition of the Hartree–Fock interaction energies into physical components (electrostatic, repulsion and relaxation energies) shows that the interaction energy in the π-conjugated is strongly dominated by the repulsion, electrostatic, and dispersion energies.