title: Composition dependent adsorption of multiple CO molecules on binary silver-gold clusters Ag(n)Au(m)+ (n + m = 5): theory and experiment.
abstract: The binding energies of multiple CO molecules to five-atom silver-gold cluster cations have been obtained employing temperature dependent gas phase ion trap measurements and ab initio calculations. The CO binding energies to Ag(n)Au(m)(+) (n + m = 5) decrease with increasing number of silver atoms. Most strikingly, after the adsorption of the fourth CO to Au(5)(+) and of the third CO to Ag(5)(+), respectively, a pronounced decrease in the binding energies of further CO molecules was observed. This is related to a CO-induced structural transformation yielding more compact metal cluster geometries. First principles calculations revealed that the exact structure of the carbonyl complexes with multiple CO and the nature of the CO-induced structural transformation strongly depend on the composition of the metal cluster as well as on the number of adsorbed CO molecules.
authors.affiliation: Institute of Surface Chemistry and Catalysis, University of Ulm, Albert-Einstein-Allee 47, 89069 Ulm, Germany.
authors.forename: Denisia M
authors.initials: DM
authors.lastname: Popolan
authors.forename: Melanie
authors.initials: M
authors.lastname: Nössler
authors.forename: Roland
authors.initials: R
authors.lastname: Mitrić
authors.forename: Thorsten M
authors.initials: TM
authors.lastname: Bernhardt
authors.forename: Vlasta
authors.initials: V
authors.lastname: Bonacić-Koutecký