Low-lying electronic states of nitrosyl cyanide (NCNO): An ab initio MCHF study

Ab initio multiconfiguration Hartree-Fock calculations of the electronic structure of several low-lying electronic states of nitrosyl cyanide (NCNO) are reported. The essential features of the electronic structure of these states were analyzed to provide a qualitative correlation diagram for the dissociation process NCNO → NC + NO. It is found that the four lowest-lying states ^1,3A′ and ^1,3A″ are connected directly to ground state products. Excitation energies and geometrical parameters for these states and for the 2-¹A″ and 2-¹A′ states are presented. Implications of these findings for NCNO photodissociation processes are discussed.