Knowledge Bank

We have previously presented the high resolution rotationally resolved laser induced fluorescence excitation spectrum of the origin band of the $A~2A1\leftarrow X~2E$ electronic transition of $CF3Oa$. We have now obtained rotationally resolved spectra for other vibrational bands of $CF3O$. In addition, we have obtained similar electronic spectra involving several vibrational transitions of $CF3S$. In both molecules, we observe excited vibrational states which are totally symmetric and ones of e symmetry, transitions to the latter probably being caused by the Jahn-Teller effect in the ground $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}E$ state. In $CF3O$, the rotational structure of e - e vibronic transitions is much more congested than that of a - e vibronic transitions. This is because the allowed rotational transitions in the a - e bands are $|\Delta K|=0$ and 1; while the allowed transitions of the a - e bands are $|\Delta K|=1$. Nevertheless, the rotational structure of the e - e bands of $CF3S$ is less congested than that of the a - e bands. The rotational transitions of the e - e bands can be divided into several sub-groups with each sub-group containing a few rotational transitions and with the sub-groups separated by about $0.5cm-1$. Overall rotational transitions of the e - e bands span $\gtrsim 6cm-1$. On the other hand, the rotational transitions of the a - e type bands of $CF3S$ span $\lesssim 4cm-1$.