Evaluation of a density functional with account of van der Waals forces using experimental data of H2 physisorption on Cu(111)

Detailed experimental data for physisorption potential-energy curves of H-2 on low-indexed faces of Cu challenge theory. Recently, density-functional theory has been developed to also account for nonlocal correlation effects, including van der Waals forces. We show that one functional, denoted vdW-DF2, gives a potential-energy curve promisingly close to the experiment-derived physisorption-energy curve. The comparison also gives indications for further improvements of the functionals.