ELECTRON-SPECTROSCOPY STUDIES OF SMALL DEPOSITED METAL PARTICLES

The Al2O3/NiAl(110) system with and without Pd clusters on the surface has been studied using photoemission of both core and valence levels. Pd has been deposited under various conditions, and changes in the sp ectra due to differences in growth modes are discussed. The C Is spect ra for CO adsorbed on deposited Pd clusters of increasing size can be viewed as showing the evolution from a deposited carbonyl-like species to CO adsorbed on a metallic surface. Heating of CO-saturated cluster s to 300 K leads to desorption of more than half of the CO, which allo ws for a stronger interaction between the remaining molecules and the Pd clusters.