A theoretical study of spectroscopy and metastability of the CN2+ dication

► Spectroscopic constants of 13 electronic states of CN2+. ► Double ionization energy of CN by MRCI and RCCSD(T) methods. ► Spin-orbit integrals of CN2+ as a function of internuclear distance. ► Tunneling and spin-orbit induced predissociation lifetimes of CN2+.