Knowledge Bank

The first electronic spectrum of the molecular ion $C2+$ was recorded in 1984 by O'Keefe et. al. in a beam of mass selected $ionsa$. Three years later, Maier and coworkers did an extensive analysis on several bands of the $B\leftarrow Xsystembcd$. While their spectra showed several perturbations, the low resolution of their experiment hindered the analysis of the perturbation and the quartet spitting. In 1993, Zackrisson and Royen obtained a high resolution spectrum of the (0,1) band and determined the molecular constants and perturbation $parameterse$. In the work that follows, velocity modulation with heterodyne detection has been used to record the (0,2) and (6,9) bands of the $B\leftarrow X$ system of $C2+$. The (0,2) band has been rotationally analyzed and the spectrum shows perturbations which are attributed to an interaction between the $B4\Sigma u-$ and the $22\Pi u$ states. Molecular constants and perturbation parameters have been obtained.