Laser-induced-fluorescence detection of SnO in low-pressure particle-synthesis flames

Ground-state SnO has been observed in a flame for the first time using laser-induced fluorescence. The (18-0) band of the E¹Σ⁺-X¹Σ⁺ transition is used for excitation. SnO is found to rapidly predissociate after excitation, and the tin atom emerges electronically excited, generating a fluorescence spectrum of atomic tin lines. This transition is found to be strong enough to excite in the linear regime, and the discrete nature of the fluorescence spectrum facilitates detection in environments with strong scattering and other interferences. However, quantitative analysis is hindered by a high density of SnO lines due to the many tin isotopes. Spatial SnO profiles in a hydrogen/oxygen/tetra-n-butyltin flame are obtained using this technique, and these profiles are qualitatively similar to metal monoxide profiles in other oxide-synthesis flames.