Reactions of size-selected metal cluster ions

Reactions of small thermalized cationic nickel clusters with carbon monoxide were investigated in a guided molecular-beam experiment. Employing this technique, an efficient nickel carbonyl cluster formation and even bond breaking of the C-O bond was observed. The stability of the nickel carbonyl complexes was measured by exciting these complexes with laser light showing an efficient photodesorption of the carbon ligands. Additionally, a very strong influence of the kinetic energy of metal clusters on the reaction yield was observed. The structure of the saturated nickel carbonyl complexes is discussed using simple electron-counting rules. The measured results show an excellent agreement with the predicted saturation numbers and thus confirm the structural attributions.