Knowledge Bank

The geometry of the excited electronic state associated with the 3800A absorption system of $SO2$ vapor has been recently determined by a quantitative application of the Frank-Condon $principle.(1)$ The results reported are $r\prime =r\prime \prime +0.0601.492$A, and $2\theta \prime =2\theta \prime \prime -5\circ 4\prime =124\circ 36\prime$. These data yield the constants of the rotational structure, namely $2\Delta (A-B¯)=0.396$ $cm-1$ and $2AB¯=-0.071cm-1$. In order to check these results, and in order to remove the uncertainty as to the polarization of the bands of this $system,(2)(3)$ the resolvable features of the rotational structure of the bands are being examined. Preliminary measurements yield $2\Delta (A-B¯)=0.438+0.03$ $cm-1$ and $2B¯=-0.080+0.008$ $cm-1$ confirming the results based on the Frank-Condon principle. Although the polarization of these bands has not yet been determined with certainty, it is expected that this can be reported soon.