RESEARCH ARTICLE Analysis of highly excited 'hot' bands in the SO2 molecule: m2Y 3m3Zm2 and 2m1Ym2Ym3Zm2

max: a ¼ 20 for the bands 3� 3 and 2� 1 þ � 3, respectively. After ‘cleaning’ the experimental spectrum from transitions belonging to the 3� 3 and 2� 1 þ � 3 bands, a variational procedure was used that allowed us to assign 230 and 115 transitions with the values of quantum numbers J max. ¼ 35, K max: a ¼ 10, and J max. ¼ 26, K max: a ¼ 11 for the bands � 2 þ 3� 3 � � 2 and 2� 1 þ � 2 þ � 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.