Density functional theory with nonlocal correlation: A key to the solution of the CO adsorption puzzle

We study the chemisorption of CO molecule into sites of different coordination on (111) surfaces of late $4d$ and $5d$ transition metals. In an attempt to solve the well-known CO adsorption puzzle, i.e., discrepancies of adsorption site preferences with experiment which appear in the standard density functional theory calculations, we have applied the relatively new van der Waals-density functional of nonlocal correlation. In all considered cases this reduces or completely solves the site preference discrepancies and improves the value of the adsorption energy. By introducing a cutoff distance for nonlocal interaction we can pinpoint the length scale at which the correlation plays a major role in the systems considered.