Formation, photodissociation, and structure studies of group 14(Si, Ge, Sn, and Pb)/P binary cluster ions

Group 14(Si, Ge, Sn, and Pb)/P binary cluster ions have been produced by la ser ablation, photodissociated by UV laser and detected with a tandem time- of-flight mass spectrometer. As expected on the double periodicities of gro up 14 elements, Si/P and Ge/P binary cluster ions, whereas Sn/P and Pb/P bi nary cluster ions, have similar compositions, respectively. The stabilities of these binary phosphide cluster ions depend on their electronic and geom etric structures, and the influence of geometric structures on the stabilit ies is increasing from Si/P cluster ions to Pb/P cluster ions. "Magic numbe rs" are observed in two types of binary phosphide cluster ions. One type of magic numbered binary cluster ions is isoelectronic to Zintl polyatomic an ions (e.g. Pb-5(2-)) in condensed phases. These binary cluster ions are com posed of group 14 metals mainly, containing only one or two phosphorus atom s. The structures and bonding scheme of these binary cluster ions can be pr edicted by using Wade's electron counting rule. Another type of magic numbe red binary cluster ions is isoelectronic either to the neutral group 14 clu sters or to the neutral phosphorus clusters, and thus may present similar s tructures as their neutral analogues. The possible structures and bonding o f the magic numbered cluster ions are further investigated with density fun ctional theory Becke-style 3 parameter using the Lee-Yang-Parr correlation functional calculations. (Int J Mass Spectrom 202 (2000) 261-271) (C) 2000 Elsevier Science B.V.