Ab initio study on the potential energy surfaces of NCO2+

Charged molecular species have special roles in upper atmosphere and interstellar regions. An ab initio calculation for NCO2+ electronic structures by cc-pVQZ/CASSCF/MRCI method is presented. The potential energy surfaces of low-lying states of NCO2+ have been explored. The ground state X 2Π and the lowest excited state a 4Σ− are metastable with a major collinear dissociation channel into N+ (X 3Pg) + CO+ (X 2Σ+). For the excited states from 3 to 8 eV the pre-dissociation processes are dominant while the states above 8 eV are repulsive. Several crossings, avoided crossings and conical intersections for NCO2+ have also been assigned.