COPPER ANTIMONY AND COPPER BISMUTH ALLOY CLUSTERS - MAGIC NUMBERS AND ELECTRONIC-STRUCTURE

Metal alloy clusters Cu(n)Sb(m) and Cu(n)Bi(m) are produced by a gas aggregation source and investigated by time-of-flight mass spectrometry following ionization with a KrF excimer laser. Two types of the magic numbers are observed in their cluster ions: magic numbers corresponding to jellium shell closings by counting the total valence electrons from the component metals, and other magic numbers explained by the polyhedral shape-electron counting scheme (Wade's rules). In the second type of magic numbers, Cu atoms give electrons to the skeleton of Sb or Bi to satisfy the total charge of the cluster ions, and simultaneously Cu atoms take the vacant vertex positions of the skeleton to form corresponding deltahedral structures (closo structures).