Metal clusters: Morphology and chemical properties

Metal cluster studies have been an active area of research for more than three decades. A major thrust of the metal cluster studies is towards the area of supported, size-selected metal clusters. We have developed an improved source which can generate greater intensities of stable cluster ions. The source is based on the laser vaporization technique and uses the 532 nm radiation from a Q-switched Nd:YAG laser. Mass selection is achieved using a Wien (E x B) filter. An electron gun, incorporated in such a way as to intercept the laser vaporized cluster ions, has been successful in creating a larger intensity of the cluster ions which has made our surface studies easier and quicker. Niobium, cobalt and manganese clusters have been successfully generated and size selected.A UHV chamber for depositing the clusters on a suitable substrate and then transferring them under vacuum to a surface analysis apparatus has been assembled for characterization of the supported clusters. The surface studies show us some interesting characteristics as far as the small clusters of niobium are concerned. We have been able to get a qualitative picture of the nature of binding of small Nb clusters (monomers through hexamers) to Ni(110) as a substrate through thermal desorption studies of CO on bare Ni(110) and cluster coated Ni(110) surfaces.U of I OnlyETDs are only available to UIUC Users without author permissio