First high resolution analysis of the 3ν₂ and 3ν₂−ν₂ bands of ³²S¹⁶O₂

The second bending overtone band 3ν₂ of sulfur dioxide has been studied for the first time with high resolution rotation-vibration spectroscopy. The 1530 transitions involving 728 upper state energy levels with J^max.= 53 and K_a ^max.= 15 have been assigned to the 3ν₂ band. The 746 transitions belonging to the 3ν₂−ν₂ “hot” band have been also assigned in the region of 950–1100 cm−1. For the analysis of the assigned transitions, an effective Hamiltonian of an isolated (030) vibrational state (the Watson operator in A-reduction and I^r representation) was used. Set of 9 varied parameters was determined which reproduce the initial experimental data with the d_rms deviations of 9.0×10⁻⁴ cm−1 and 9.8×10⁻⁴ cm−1 for the 3ν₂ and 3ν₂−ν₂ bands, which are comparable with the experimental uncertainties.