Knowledge Bank

High resolution Raman spectra of $CD3Cl$ vapor has been recorded ($\Delta \nu$ between 0.05 to $0.30cm-1$). The $\nu 1(A1)$ and $\nu 4$ (E) hands will be discussed here. The two sets of subbands ($\Delta K=\pm 1,\Delta K=\pm 2$) allowed for a $C3v$ type molecule permit a direct determination of the axial rotational constant $A0$. Using the following ground state combination differences on the observed Q branch maxima, $$ \frac{^{R}Q_{K-1}- {^{O}Q}{K+2}}{(6K+3)}=\frac{^{S}Q{K-1}- {^{P}Q}{K+2}}{(6K+3)}=(A{0} - B_{0}) -D_{K} (2K^{2} + 2K + 5) $$ we obtained the following preliminary results: \begin{eqnarray*} A_{0} &=& 2.610 \pm 0.003 cm^{-1} \ D_{k} &=& (5 \pm 3) \times 10^{-5} cm^{-1} \end{eqnarray*} No evidence of the isotopic splitting was observed, so an effective $B0$ of 0.360 127 $cm-1$ was used. The $\nu 1$ band Q branch was resolved and showed its K components resolved with clear intensity alternation visible for K = 3p levels.