Adsorption of Aromatic Hydrocarbons on Graphene: From Energy Decomposition to Stable Adsorption Geometries

The quantitative prediction of the π-π interaction energetics of the adsorption of polycyclic aromatic hydrocarbons (PAHs) on graphene remains a challenge, prompting the need for computationally efficient yet reliable methods. Herein, we investigated the intermolecular interactions of aromatic hydrocarbons, benzene, naphthalene, anthracene, pyrene, and coronene, with differently-sized nanographene models using the symmetry-adapted perturbation theory (SAPT) approach at the SAPT0 level. Convergence analysis of the total intermolecular interaction energies and the intervening components established circumcircumcoronene as the smallest nanographene model that can model the adsorption of the chosen aromatic hydrocarbons. The SAPT0 energies were then employed as the reference data for parametrizing an anisotropic analytic potential, namely the PAH anisotropic potential (PAHAP). The thus-parametrized PAHAP was subsequently employed to predict the most stable adsorption geometries of aromatic hydrocarbons over graphene. The estimated interaction energies and equilibrium distances differed significantly from those obtained using the original PAHAP parametrized against SAPT(DFT) interaction energies for small PAH dimers (J. Chem. Theory Comput., 2010, 6, 683-695). Nonetheless, single-point density functional theory electronic energy computation of both sets of PAHAP data yielded very similar energies, suggesting the competence of PAHAP parametrized against a comparatively low-demand computational approach like SAPT0 in modeling π-π interactions.