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We present a detailed study of the adsorption of CO on Cu, Rh,
and Pt (111) surfaces in top and hollow sites. The study has been
performed with a gradient corrected functional (PBE) and PBE0 and
HSE03 hybrid Hartree-Fock density functionals within the framework
of generalized Kohn-Sham density functional theory using a plane-wave
basis set. As expected, the gradient corrected functional shows the tendency
to favor the hollow sites, at variance with experimental findings
that give the top site as the most stable adsorption site. The PBE0
and HSE03 functionals reduce this tendency. Indeed, they predict the
correct adsorption site for Cu and Rh but fail for Pt. But even in this
case, the hybrid functional destabilizes the hollow site by 50 meV compared
to the GGA description. This suggests that hybrid functionals
give an overall better description of the chemisorption of CO molecules
on metal surfaces, but, in general, they still do not predict the correct
adsorption site.The study of the effect of hybrid functionals on CO adsorption is extended to other 4d and 5d metal surfaces. |