Ionization potentials of oxidized copper clusters

The ionization potential (IP) of CunO2 clusters (n = 15−46) has been measured and the shift in IP induced by the adsoprtion of the O2 molecule evaluated. There are no large discontinuities in the IP of CunO2, in contrast with the electronic shell closings observed for pure Cun, but the even-odd alternation in the IP persists upon oxidation. On average, the IP increases after oxidation, with larger shifts for clusters where the pure Cun have low IP (n = 21, 41) and small or negative shifts for clusters originally having high IP (n = 30, 34, 40).