Knowledge Bank

Some bands of the 3880\AA triplet-singlet system of sulfur dioxide have been rotationally analyzed. The transitions observed are $\Delta K=\pm 1,\Delta N=0,\pm 1$ 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: $F1$ component, $\Delta N=0$ and $-2$; $Fi$ component, $\Delta N=\pm 1$ ; and in the $F3$ component, $\Delta N=0$ and $+2$. The active spin function is therefore $a2>$. Together with the identity of “missing” levels, the results prove that the upper state of the transition is $\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}B1$, 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]