Knowledge Bank

A supersonic free-jet spectrum of the $\nu 4$ band of CF$3$Cl has been measured using a quantum cascade laser system. Those measurements were combined with a low temperature (-67 C) FTS spectrum of the region 1060 to 1260 cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$ to give improved values for the rovibrational constants for the $\nu 1$, 2$\nu 5$, and $\nu 4$ states of the CF$\mathrm{3<mrow\; data-mjx-texclass="ORD">35</mrow>}$Cl AND CF$\mathrm{3<mrow\; data-mjx-texclass="ORD">37</mrow>}$Cl. The principal perturbation found by earlier investigators in the $\nu 1$ band is treated as a very weak Coriolis interaction at several avoided crossings of the rotational levels of the $\nu 1$ state and the 2$\nu 5$ state with {\em kl} $<0$. Room temperature FTS measurements were also made for the region 400 to 970 cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$. With these new measurements we now have high resolution data on the states $\nu 1$, $\nu 2$, $\nu 3$, $\nu 4$, and $\nu 5$. Also included in this analysis are the overtones 2$\nu 3$ and 2$\nu 6$ and a few hot bands.