We have searched for new species of small oxygen-containing gas-phase dianions produced in a secondary ion mass spectrometer by Cs+ ion bombardment of solid samples with simultaneous exposure of their surfaces to O2 gas. The targets were a pure zinc metal foil, a copper-contaminated zinc-based coin, two silicon-germanium samples (Si 1-xGex (with x = 6.5% or 27%)) and a piece of titanium metal. The novel dianions Zn3O42-, Zn 4O52-, CuZn2O4 2-, Si2GeO62-, Ti2O 52- and Ti3O72- have been observed at half-integer m/z values in the negative ion mass spectra. The heptamer dianions Zn3O42- and Ti 2O52- have been unambiguously identified by their isotopic abundances. Their flight times through the mass spectrometer are ∼20 μs and ∼17 μs, respectively. The geometrical structures of the two heptamer dianions Ti2O52-, and Zn 3O42- are investigated using ab initio methods, and the identified isomers are compared to those of the novel Ge 2O52- and the known Si2O 52- and Be3O42- dianions.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry