Analysis of highly excited 'hot' bands in the SO₂ molecule: 2v₂ + 3v₃ - 2v₁ and 2v₁ + v ₂ + v₃ - v₂

We set up a variational procedure of assignments of transitions and we applied it to the analysis very weak 'hot' bands, 2 + 33 - 2 and 21 + 2 + 3 - 2, of the SO2 molecule. As the first step of the study, the 'cold' bands, 33 and 21 + 3, are re-analysed and transitions belonging to those bands are assigned up to the values of quantum numbers Jmax. = 60, [image omitted], and Jmax. = 69, [image omitted] for the bands 33 and 21 + 3, respectively. After 'cleaning' the experimental spectrum from transitions belonging to the 33 and 21 + 3 bands, a variational procedure was used that allowed us to assign 230 and 115 transitions with the values of quantum numbers Jmax. = 35, [image omitted], and Jmax. = 26, [image omitted] for the bands 2 + 33 - 2 and 21 + 2 + 3 - 2, respectively. The sets of spectroscopic parameters obtained by fitting the assigned experimental transitions reproduce the initial experimental data with an accuracy close to experimental uncertainties.