The dynamic interaction of CO with Ru(0001) in the presence of adsorbed COand hydrogen

This study deals with the dynamic interaction of CO with the bare Ru(0001), the fully hydrogen- and fully CO-covered ruthenium surface. Molecular beam techniques are applied to investigate the potential energy surface of the ruthenium CO interaction and the chemically modified surfaces. The clean su rface shows all properties of a deep uniform chemisorption well with a stro ng rotational anisotropy. The strong chemically attractive interaction can be diminished by CO adsorption, which leads to zero sticking, even at trans lational energies as high as 1.2 eV. The angular distribution shows a subst antial broadening compared to the clean surface. As shown recently, in the case of hydrogen, CO adsorption turns into an activated process with the at op position being the only available adsorption site. Scattering CO molecul es from the hydrogen-covered surface leads to very narrow angular distribut ions. The collisions are mainly quasi-elastic. (C) 2000 Elsevier Science B. V. All rights reserved.