Photoelectron spectroscopic studies of adsorption of CO and oxygen on Ru(001)

XPS and UPS have been used for a detailed study of the adsorption and coadsorption of CO and oxygen on a clean Ru(001) single crystal. The measured substrate and adsorbate core level binding energies and valence levels are discussed. The O 1s XPS peak intensity has been used for kinetic studies of adsorption and coadsorption. Some studies of the angular dependence of adsorbate and substrate peak intensity ratios are presented. We also present data on the shifts of XPS peaks and changes in UPS spectra as a function of adsorbate coverage. The data are correlated with the results of earlier measurements with other methods.