Theoretical study of the low-lying electronic states of the CN2+ dication

Ab initio computations are performed using multi-reference configuration interaction technique and augmented quintuple-zeta basis set to investigate the low-lying electronic states of the CN2+ dication. The electronic ground state of this dication appears to be of X4Σ− nature and possesses a potential well of about 0.85 eV. Several excited states of this doubly charged molecule also depict such potential wells. The rotational and vibrational spectroscopic constants of these bound metastable states have been computed. The adiabatic double ionization energy of CN was deduced at 37.5 eV from the potential energy curves of the electronic ground states of the CN and CN2+ species. The double ionization spectra of CN was also simulated by the computations of the Franck–Condon factors.