Abstract:

 The formation and photodissociation of group Ⅳ(Si,Ge,Sn,Pb)/P binary cluster ions ,produced by laser ablation, were studied with a tandem TOF mass spectrometer. The stability of these cluster ions is influenced by their electronic and geometric structures ,and the geometric stability becomes more important for heavier group Ⅳ/P cluster ions. Two types of binary clusters marked with the magic numbers were observed: one type of magic clusters may be explained by the Wade's rule, in which P atom either attaches as electron-donating ligand to the closo-skeleton of group Ⅳatoms, or joins the closo-skeleton directly; another type of magic clusters are isoelectronic with magic species of neutral group Ⅳclusters or P clusters. The possible structures of magic cluster ions were studied by ab initio calculation and the Wade's rule.

Key words: Binary atomic clusters, Laser ablstion, Laser photodissociation, TOF mass spectrometer, Wades rule