ROTATIONAL ANALYSIS OF THE $^{3}B_{1}\leftarrow^{1}{A}_{1}$ BANDS OF SULFUR DIOXIDE

Author Institution: Photochemistry Unit, University of Western OntarioSome bands of the 3880\AA triplet-singlet system of sulfur dioxide have been rotationally analyzed. The transitions observed are $\Delta{K} = \pm1, \Delta{N} = 0, \pm 1$ and $\pm$2, with small spin-rotation and spin-spin interaction characteristic of case (b) coupling. In the asymmetric region of the band the strong sub-branches are: $F_{1}$ component, $\Delta{N} = 0$ and $-2$; $F_{i}$ component, $\Delta{N} = \pm 1$ ; and in the $F_{3}$ component, $\Delta{N} = 0$ and $+ 2$. The active spin function is therefore $a_{2}>$. Together with the identity of “missing” levels, the results prove that the upper state of the transition is $^{3}B_{1}$, in agreement with simple m.o. predictions. Constants for the 0-0 band are given (in $cm^{-1}$) in the Table below. Results for other transitions in the system will be discussed. [FIGURE