Knowledge Bank

The Raman spectrum of gaseous cyanogen was studied under high resolution using techniques described $elsewhere.1,2$ The pure rotational, spectrum was photographed in 4 1/2 and 6 1/2 hours using a gas pressure of 50 torr and a spectral slit width of $0.025cm-1$. The pure rotational spectra in the ground state as well as in the $\nu 5$ and $2\nu 5$ excited states were observed. The rotation-vibration spectrum in the neighborhood of the band was photographed in 11 and 15 hours using a gas pressure of 200 torr and a spectral slit width of $0.060cm-1$. The ``hot” band transitions $\nu 1+\nu 5-\nu 5$ and $\nu 1+2\nu 5-2\nu 5$ were also observed. The following molecular constants, all in units of $cm-1$, were determined. From the pure rotation specturm (S-branch transitions only): \begin {eqnarray*} B_{(00000)}=0.157218 \pm 0.000004; \ \ D_{(00000)}=(3.08 \pm 0.03) \times 10^{-8}\ B^{c}{(00001)}=0.157375 \pm 0.000011; \ \ D^{c}{(00001)}=(0.96 \pm 0.09) \times 10^{-8}\ B^{d}{(00001)}=0.157494 \pm 0.000016; \ \ D^{d}{(00001)}=(1.03 \pm 0.14) \times 10^{-8}\ \end {eqnarray*} From the rotation-vibration spectrum: \begin {eqnarray*} \nu_{1} \ band: \quad \quad \quad \quad \nu_{1}=2330.515 \pm 0.002 \ B_{(10000)}=0.156394 \pm 0.000011; \ \ D_{(10000)}=(3.39 \pm 0.28) \times 10^{-8}\ B_{(00000)}=0.157216 \pm 0.000012; \ \ D_{(00000)}=(3.61 \pm 0.32) \times 10^{-8}\ \nu_{1} +\nu_{5}-\nu_{5}\ band : \quad \quad \quad \nu_{1} +\nu_{5}-\nu_{5}\ =2327.667 \pm 0.002\ B_{(10001)}=0.156856 \pm 0.000023; \ \ D_{(10001)}=(3.02 \pm 1.56) \times 10^{-8}\ B_{(00001)}=0.157766 \pm 0.000021; \ \ D_{(00001)}=(10.0 \pm 1.3) \times 10^{-8}\ \end {eqnarray*} These results will be discussed in the light of available infrared $data.3-5$ Further work is in progress. This work was supported, in part, by a grant from the National Science Foundation.