Investigation of CO Adsorption on Cs/Ru(1010) Surface Using ARUPS

CO adsorption on Ru(1010) and Cs/Ru(1010) surfaces has been investigated using ARUPS, at low temperature 150K. The 5��+1�� and 4�� levels of CO molecule were found in angle-resolved UP spectra showing that CO is in molecular adsorption states on clean and Cs precovered Ru(1010). The dependence of CO 4�� intensity on incident angle suggests that adsorbed CO stands upright on clean Ru(1010) surface; But adsorbed CO, with a short-range interaction with Cs atom [15], does not stand upright and tilts in ��1210�� azimuth on a Cs-precovered Ru(1010) surface.