Isotopic effect of Cl2+ rovibronic spectra in the A-X system

This paper studies the isotopic effect of Cl$_{2}^{ + }$ rovibronic spectra in the $A^{2}\Pi _{\rm u }$ ($\Om = 1/2) - X^{2}\Pi _{\rm g}$ ($\Om= 1/2$) system. Based on the experimental results of the molecular constants of $^{35}$Cl$_{2}^{ + }$, it calculates the vibrational isotope shifts of the (2, 7) and (3, 7) band between the isotopic species $^{35}$Cl$_{2}^{ + }$, $^{35}$Cl$^{37}$Cl$^{ + }$ and $^{37}$Cl$_{2}^{ + }$, and estimates the rotational constants of both $ A^{2}\Pi _{\rm u}$ and $X ^{2}\Pi _{\rm g}$ states for the minor isotopic species $^{35}$Cl$^{37}$Cl$^{ + }$ and $^{ 37}$Cl$_{2}^{ + }$. The experimental results of the spectrum of $^{35}$Cl$^{37}$Cl$^{ + }$ (3, 7) band proves the above mentioned theoretical calculation. The molecular constants and thus resultant rovibronic spectrum for $^{37}$Cl$_{2}^{ + }$ were predicted, which will be helpful for further experimental investigation.