Knowledge Bank

The vibration-rotation spectrum of the $v2$ and $v5$ fundamentals of $CDF3$, the $v1$ fundamental of $CBrF3$, and the $v4$ fundamental of $CD4$ have been recorded using a Nicolet 7199 Fourier Transform Infrared Spectrometer. In addition, the Q-branch and several R(J) and P(J) sub-bands of each of these transitions have been investigated using a tunable semiconductor diode laser spectrometer. In $v2(CDF3)$, the Q-branch and the K-structure in the P(J) subbands are resolved and assigned for the first time. Constants derived for this band are (in $cm-1$) \begin{eqnarray*} v_{2} = 1111.1823_{6} \quad \alpha_{2}^{B} = 0.001646_{11} \quad D_{\alpha}^{J} = (2.5+0.5) \times 10^{-7} \ A_{2} =0.018623_{4} \quad \alpha{ _{2}}^{A}- \alpha _{2}^{B} = 0.001238_{9} \quad D_{2}^{J} = (3.4+0.5) \times 10^{-7}; \\ B_{2} = 0.32928_{2} \quad D_{2}{^{J}} =D_{D}{^{J}} = (9+4) \times 10^{-8} \end{eqnarray*} these are nearly 100 times more precise than those reported in previous $work.1$ Improved constants will also be reported for $CBrF3$ and $CD4$.