Knowledge Bank

The double resonance spectrum of $NO2$ has been observed between three ground state millimeter wave transitions and the optical $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}B$ electronic state region. The probed ground state transitions were the $N=2,4$, and $10,K=0-1Q$ branches near 250 GHz, and the optical range scanned was $16800cm-1$ to $16950cm-1$. The 10(0.10) - 10(1.9) F2 spectrum, when combined with results on the 9(1,9) - 10(0.10) F1 spectrum, establish violations of the selection rule, so that N is not a good quantum number in the upper state. The fraction of all possible symmetry-restricted basis states which contribute to a typical eigenstate, measured by Heller's F parameter, is similar for the three N values, but is greater for $K=1$ than for $K=0$. By identifying upper states in common. R lines from $N=2$ and P lines from $N=4$ have been identified.