Characteristic energy loss measurements of slow electrons on clean and adsorbate-covered Ru(001)

Characteristic energy losses of low energy electrons backscattered from Ru(001) have been measured under conditions of very low primary electron currents for the clean and the CO- or oxygen-covered surface. The main losses found for the clean and the CO-covered surface are similar to those observed as XPS core satellites which may mean that the influences of the core hole on the initial and the final states of the valence shake-up are about the same. A peak in the secondary electron spectrum of the clean surface is found at 11 eV which is changed by adsorption. The results are discussed in terms of the excitations of the metal and the adsorbates.