Identification of the S O vibronic bands in the 31120-32160 cm-region 34 16 2 1

Single vibronic level fluorescence spectra of bands in the 31120-32160 cm⁻¹ region of SO₂ were measured under low rotational temperature conditions in an expanded supersonic jet. Eight weak bands were confirmed as belonging to the ³⁴S¹⁶O₂ system : their resonance vibrational transitions were found to match the term energies of this isotope. The correlating bands in the ³²S¹⁶O₂ system were identified by noting that the Franck-Condon patterns of their dispersed fluorescence spectra were similar to those of the ³⁴S¹⁶O₂ bands. The analysis of the spectra also concludes that some of the weak bands in the above region can be due to ³²S¹⁶O₂ bands whose upper levels have B^ev₂ = B^e₂ × a^v₁ vibronic symmetry.