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.