On the Π u 2 → Π g 2 Bands of C O 2 + . Part II

In continuation of the first part of the work containing the rotational analysis of 10 sub-bands belonging to the progression $v^{\ensuremath{'}\ensuremath{'}}_{1}=0$ of the $^{2}\ensuremath{\Pi}_{u}\ensuremath{\rightarrow}^{2}\ensuremath{\Pi}_{g}$ band system of C${\mathrm{O}}_{2}^{+}$, 24 new sub-bands were analyzed. These bands belong to the progressions ${{v}^{\ensuremath{'}\ensuremath{'}}}_{1}$ and ${{v}^{\ensuremath{'}\ensuremath{'}}}_{1}=2$. It was found that the substate $^{2}\ensuremath{\Pi}_{\frac{3}{2}g}$, ${{v}^{\ensuremath{'}\ensuremath{'}}}_{1}=1$ is split into two levels, the splitting being probably caused by an interaction (resonance) with some other unidentified substate (very probably one of the vibronic substates corresponding to two quanta of bending vibration). A similar splitting was found in the substate $^{2}\ensuremath{\Pi}_{\frac{3}{2}u}$, $v^{\ensuremath{'}}_{1}=4$. Weaker perturbations, manifested by anomalous $B$ values, $\ensuremath{\Lambda}$-doubling increasing proportionally to about ${J}^{2.5}$, and shifts of vibrational levels were detected in several other vibrational levels. A selection rule forbidding transitions between vibrational levels showing opposite perturbation shifts in the vibrational energy has been found. The new constants obtained are: $\ensuremath{\Delta}G^{\ensuremath{'}\ensuremath{'}a}_{1}=1241.77$, $\ensuremath{\Delta}G^{\ensuremath{'}\ensuremath{'}b}_{1}=1287.32$, $\ensuremath{\Delta}G^{\ensuremath{'}\ensuremath{'}b}_{2}=1209.55$ (all $^{2}\ensuremath{\Pi}_{\frac{3}{2}g}$). $\ensuremath{\Delta}G^{\ensuremath{'}\ensuremath{'}}_{1}=1265.75$, $\ensuremath{\Delta}G^{\ensuremath{'}\ensuremath{'}}_{2}=1256.89$ ($^{2}\ensuremath{\Pi}_{\frac{1}{2}g}$); $\ensuremath{\Delta}G^{\ensuremath{'}a}_{4}=1062.50$, $\ensuremath{\Delta}G^{\ensuremath{'}b}_{5}=1055.25$, $\ensuremath{\Delta}G^{\ensuremath{'}}_{6}=1103.97$ ($^{2}\ensuremath{\Pi}_{\frac{3}{2}u}$); $\ensuremath{\Delta}G^{\ensuremath{'}}_{5}=1108.50$, $\ensuremath{\Delta}G^{\ensuremath{'}}_{6}=1106.99$ ($^{2}\ensuremath{\Pi}_{\frac{1}{2}u}$). Further, for $^{2}\ensuremath{\Pi}_{\frac{3}{2}g}$, $B^{\ensuremath{'}\ensuremath{'}a}_{1}=0.3754$, $B^{\ensuremath{'}\ensuremath{'}b}_{1}=0.3814$, $B^{\ensuremath{'}\ensuremath{'}}_{2}=0.3769$; for $^{2}\ensuremath{\Pi}_{\frac{1}{2}g}$, $B^{\ensuremath{'}\ensuremath{'}}_{1}=0.3803$, $B^{\ensuremath{'}\ensuremath{'}}_{2}=0.3793$; for $^{2}\ensuremath{\Pi}_{\frac{3}{2}u}$, $B^{\ensuremath{'}a}_{4}=0.3421$, $B^{\ensuremath{'}}_{5}=0.3427$, $B^{\ensuremath{'}}_{6}=0.3417$; for $^{2}\ensuremath{\Pi}_{\frac{1}{2}u}$, $B^{\ensuremath{'}}_{5}=0.3460$, $B^{\ensuremath{'}}_{6}=0.3458$. The values of the constants reported in Part I are corrected and the $\ensuremath{\Lambda}$-doubling for all levels is evaluated. Formulas for unperturbed values of $B$ (both substates $^{2}\ensuremath{\Pi}_{\frac{3}{2}}$ and $^{2}\ensuremath{\Pi}_{\frac{1}{2}}$ are: $^{2}\ensuremath{\Pi}_{g}B^{\ensuremath{'}\ensuremath{'}}_{v}=B^{\ensuremath{'}\ensuremath{'}}_{0}\ensuremath{-}0.0012v^{\ensuremath{'}\ensuremath{'}}_{1}$, $^{2}\ensuremath{\Pi}_{u}B^{\ensuremath{'}}_{v}=B^{\ensuremath{'}}_{0}\ensuremath{-}0.0011v^{\ensuremath{'}}_{1}$; for unperturbed zero band lines ${\ensuremath{\nu}}_{{v}^{\ensuremath{'}}{v}^{\ensuremath{'}\ensuremath{'}}}={\ensuremath{\nu}}_{00}+1131v^{\ensuremath{'}}_{1}\ensuremath{-}3v^{\ensuremath{'}}_{1}(v^{\ensuremath{'}}_{1}+1)\ensuremath{-}1280v^{\ensuremath{'}\ensuremath{'}}_{1}+7.25v^{\ensuremath{'}\ensuremath{'}}_{1}(v^{\ensuremath{'}\ensuremath{'}}_{1}+1)$.