Electron induced dissociation of CO on Ru(001): A study by thermal desorption and electron spectroscopies

CO adsorbed on Ru cannot convert thermally into a β-state of the kind observed on W and Mo — which is most probably dissociated CO — under CO pressures below 10^?5 Torr. Such a state can, however, be produced by electron impact onto a virgin CO layer adsorbed on Ru. This is shown using temperature-programmed desorption, UPS, XPS, XPS satellites, and XAES. A comparative discussion of the β-states on W and Ru yields rough estimates of the energies for desorption and conversion of CO on these metals; possible implications for catalytic reactions are mentioned.