This interpretation is supported by the results of the charge analysis on the Ru adsorption site and the charge transfer to the CO. Using the Ru adsorption sites listed in Table for Ovacancies in deeper layers, we find little variation in the electron charge on the respective Ru adsorption sites, both for the interface (i) and interface (ii) adsorption site, except for a decrease on the interface (i) site and a significantly stronger increase for interface (ii) adsorption in the presence of an O-vacancy on the (ii) site (Figure , Table ). Hence, the much higher CO adsorption energy on the interface (i) site of the 1VO(ii) system is not reflected by a higher charge on this Ru adsorption site, while for adsorption on the interface (ii) site these trends would be comparable. For adsorption on the interface (ii) site, the increase in charge on the adsorption site results. For both sites, the changes in charge are reversed again for deeper lying O-vacancies.