Knowledge Bank

The 3600 {\AA} absorption system of $ClO2$ includes bands which involve vibrational excitation in the antisymmetrical coordinate $Q3\prime$. A previously reported $calculation1$ was partly successful in explaining the intensities and the isotope shifts of these bands in terms of a double-minimum potential in the $Q3\prime$ coordinate. A new calculation based on a slightly modified vibrational analysis yields considerably better agreement with experiment. The observed intervals are $1+-0+=898cm-1$ and $2+-1+=988cm-1$. The barrier of the double-minimum potential is $1130cm-1$. Similar results are obtained for the excited states of the 2300 {\AA} system of $SO2$ and the 2400 {\AA} system of $NO2$. For $SO21+-0+=560cm-1$ and the barrier is $656cm-1$. For $NO21+-0+=713cm-1,2$ and the barrier is approximately $800cm-1$.