Benchmark calculations of water–acene interaction energies: Extrapolation to the water–graphene limit and assessment of dispersion–corrected DFT methods

Abstract

In a previous study (J. Phys. Chem. C, 2009, 113, 10242–10248) we used density functional theory based symmetry–adapted perturbation theory (DFT–SAPT) calculations of water interacting with benzene (C₆H₆), coronene (C₂₄H₁₂), and circumcoronene (C₅₄H₁₈) to estimate the interaction energy between a water molecule and a graphene sheet. The present study extends this earlier work by use of a more realistic geometry with the water molecule oriented perpendicular to the acene with both hydrogen atoms pointing down. We also include results for an intermediate C₄₈H₁₈ acene. Extrapolation of the water–acene results gives a value of −3.0 ± 0.15 kcal mol⁻¹ for the binding of a water molecule to graphene. Several popular dispersion-corrected DFT methods are applied to the water–acene systems and the resulting interacting energies are compared to results of the DFT–SAPT calculations in order to assess their performance.