Knowledge Bank

The $\nu 2$ vibrational bands of $CD3\mathrm{<mrow\; data-mjx-texclass="ORD">79</mrow>}Br(991-397cm-1)$ and $CD381(991.388cm-1)$ have been recorded by an infrared-microwave sideband laser spectrometer. More than 100 rovibrational transitions have been assigned and analyzed for each species. In each case, it was necessary to include the effects of Coriolis coupling to the corresponding $\nu 5$ band. In addition, the frequencies of approximately 200 pure quadrupole transitions have been measured for each species to an accuracy of few kHz by the method of infrared radio frequency double resonance. The infrared-microwave sideband laser operating in the cavity mode was used as the pumping source for the double resonance experiments. Newly-determined rovibrational parameters for the ground and $\nu 2=1$ states will be reported for the two isotopic species. Quadrupole coupling constants, including centrifugal distortion terms, and spin-rotation interaction constants will also be presented.