Extension of the Violet CN Band System to Include the CN Tail Bands

Measurements of fine-structure lines of tail bands.—Wave-numbers of band lines accurate to about 0.02 ${\mathrm{cm}}^{-1\mathrm{}}$ are given for 13 of the CN tail bands as excited by the reaction of acetylene with active nitrogen. The table also includes estimated intensities of the lines. Each band has a doublet $P$ and a doublet $R$ branch like the stronger violet CN bands, but the doublet separations vary markedly, being undetectable in the majority of the bands. Large perturbations, which affect several lines of each branch, are also found.