Formation of antimony oxide clusters by gas aggregation

SbxOy clusters are produced by using a gas aggregation technique. Antimony vapor is mixed with He/O-2 or He/N2O and cooled in a reaction channel. After photoionisation with a KrF (248 nm) or ArF (193 nm) excimer laser the products are mass analyzed in a time of flight mass spectrometer. In the presence of N2O no oxide clusters besides SbO+ can be detected, while with oxygen under similar experimental conditions dramatic changes can be observed. At low oxygen partial pressure the obtained spectra are dominated by the pure Sb-x(+) clusters with low intensity of SbxOy+, whereas at high oxygen partial pressure antimony oxides following the general sequence SbO+(Sb2O3)(n) are most abundant. The same stable species can furthermore be produced via aggregation of vaporised solid antimony oxide (Sb2O3). Within these experiments another new Series of antimony oxides tentatively assigned to (Sb2O3)(n)(+) appeared in the mass spectra.