Rotational Analysis of the Perturbed (13,15)Σ2−Σ2N2+ Band

A rotational analysis of the 13,15 ${}_{}{}^2{}_{}{}^{}\Sigma -{}_{}{}^2{}_{}{}^{}\Sigma$ ${N_2}^{+}$ band has been made. This analysis is of interest as a perturbation is found to occur in the upper state. The rotational analysis gives the following constants: ${B_{13}}^{\prime }={1.54}_5$ ${\mathrm{cm}}^{-1\mathrm{}}$, ${D_{13}}^{\prime }=-5\mathrm{}\times {10}^{-5\mathrm{}}$ ${\mathrm{cm}}^{-1\mathrm{}}$, ${B_{15}}^{\prime \prime }=1.62\mathrm{}$ ${\mathrm{cm}}^{-1\mathrm{}}$ and ${D_{15}}^{\prime \prime }=-1\mathrm{}\times {10}^{-5\mathrm{}}$ ${\mathrm{cm}}^{-1\mathrm{}}$. The origin of the band is at 21044.7 ${\mathrm{cm}}^{-1\mathrm{}}$.