Interaction of Cu cluster anions (Cu−n, n = 8–11) with oxygen

Abstract. The reaction of oxygen with Cu cluster anions consisting of 6–11 atoms was studied by means of Time-of-Flight mass (TOF) spectroscopy and Ultraviolet Photoelectron Spectroscopy (UPS). Using molec-ular oxygen, we found that a Cu−n cluster (n = 6−11) can react only with one single oxygen molecule, which adsorbs molecularly, implying that the clusters studied here are less reactive towards oxygen chemisorption compared to the smaller clusters (n < 5). This result indicates that chemical properties can alter signifi-cantly with increasing cluster size. Depending on the cluster source conditions, different cluster structures and reactivity patterns were found. These results are used to qualitatively describe the chemisorption energetics of oxygen on Cu cluster anions. PACS. 33.60.Cv Ultraviolet and vacuum ultraviolet photoelectron spectra – 36.40.Jn Reactivity of clusters – 36.40.Mr Spectroscopy and geometrical structure of clusters – 36.40.Wa Charged clusters