GAS-PHASE ION-MOLECULE REACTIONS IN PHOSPHINE GERMANE MIXTURES STUDIED BY ION TRAPPING

Gaseous mixtures of phosphine and germane have been investigated by io n trap mass spectrometry. Reaction path ways together with rate consta nts of the main reactions are reported. The mechanisms of ion/molecule reactions have been elucidated by single and multiple isolation steps . The GeHn+ (n = 1-3) ions react with phosphine to give GiePH(n)(+) (n = 2-4) ions. The GePH4+ ion further reacts with GeH4 to yield Ge2PH6. The GePHn+ (n = 2-4) mixed ionic family also originates from the Pphosphine primary ion, as well as from the P2Hn+ (n = 0-3) secondary i ons of phosphine reacting with neutral germane and from Ge2H2+ reactin g with phosphine. The main reaction pathways of the PHn+ (n = 0-2) ion s with GeH4 lead to the formation of the GeH2+ and GeH3+ ionic species . Protonation of phosphine from different ionic precursors is a very c ommon process and yields the stable phosphonium ion, PH4+. Trends in t otal abundances of secondary GePHn+ (n = 2-4) ions as function of reac tion time for different PH3/GeH4 pressure ratios show that excess of g ermane slightly affects the nucleation of mixed Ge-P ions.