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

►The low-lying electronic states of the CN2+ dication were investigated using multi-reference configuration interaction technique. ► The electronic ground state and several excited states of this dication depict bound structure. ► The double ionization energy of CN was computed to be 37.5 eV. ► The Franck-Condon double ionization spectrum of CN was simulated. ► Three excited states mainly composed this spectrum whereas the electronic ground state of CN2+ appear with very low relative intensity because of unfavobrable Franck-Condon factors.