Evaluation of a density functional with account of van der Waals forces using experimental data of H${}_2$ 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.

Figure 1

Experimentally determined effective physisorption potential for H${}_2$ on Cu(111),[3] compared with potential-energy curves for H${}_2$ on Cu(111), calculated for the atop site in GGA-revPBE, GGA-PBE, vdW-DF2, and vdW-DF.

Figure 2

Interaction potential for H${}_2$ on Cu(111) calculated self-consistently with the vdW-DF2 functional[9] in the bridge, hollow, and atop sites.