Adsorption of Rare-Gas Atoms and Water on Graphite and Graphene by van der Waals-Corrected Density Functional Theory

The recently developed, efficient DFT/vdW-WF method for the inclusion of the van der Waals interactions in density functional theory (DFT), based on the use of the maximally localized Wanner functions, is applied to the study of the adsorption of rare-gas atoms (He, Ar, and Xe) and a water molecule on graphite and graphene surfaces, at three high-symmetry sites, by evaluating the equilibrium binding energies and distances. The results, compared to previous theoretical calculations and experimental estimates, are promising, particularly considering that the method is free from system-dependent fitted parameters. The crucial role of the chosen reference DFT functional is discussed in detail, and possible strategies to improve the method and overcome some present limitations are proposed.