Matrix isolation studies on the co-condensation reactions of molecular SiO and GeO: the characterisation of the novel cyclic species SiGeO2, Si2GeO3 and SiGe2O3

Abstract

Matrix isolation IR studies, together with DFT calculations, have established that the co-condensation of molecular SiO and GeO in low temperature (12 K) nitrogen matrices leads to the formation of the novel silicon germanium oxide species SiGeO(2), Si(2)GeO(3) and SiGe(2)O(3) analogous to the known dimer and trimer species M(2)O(2) and M(3)O(3) (M = Si, Ge). Controlled diffusion studies in the temperature range 20-34 K result in a significant increase in trimer formation, which implies a very low activation energy for this oligomerisation step. Characteristic IR modes are assigned for all three novel mixed oxide molecules, and the DFT calculations establish that these species have cyclic C(2v) structures and provide estimates for their geometrical parameters. The significance of these results is noted in the light of current interest in the properties of mixed Si/Ge oxide systems.