Quantum Chemical Estimation of Acetone Physisorption on Graphene Using Combined Basis Set and Size Extrapolation Schemes

The physisorption of an acetone molecule on hexagonal graphene nanoflakes with increasing size has been investigated using a variety of quantum chemical methods capable of describing weak intermolecular interactions: coupled-cluster theory (CCSD and CCSD(T)), second-order Møller-Plesset perturbation theory with and without spin-component scaling (SCS-MP2 or standard MP2), long-range corrected density functional theory combined with a van der Waals functional (LC-BOP+ALL), meta-generalized gradient approximation functionals (M06-2X and M05-2X), and the dispersion augmented self-consistent-charge density functional tight-binding (SCC-DFTB-D) method. Our benchmark results for model systems as large as dicircumcoronene C₉₆H₂₄ have confirmed the suitability of the SCS-MP2 method for this specific system and the satisfactory performance of the computationally much more economical semiempirical SCC-DFTB-D method. The latter delivers a qualitatively accurate description of physisorption for flakes containing more than 800 carbon atoms. We predict accurate interaction energies of acetone with an infinitely large, defect-free graphene monolayer by combining extrapolation approaches for both increasing ab initio basis sets and graphene flake size in a two-dimensional extrapolation scheme.