IONIZATION ENERGIES OF THE ISOMERS OF $CN_{2}$

Author Institution: Cherry L. Emerson Center for Scientific Computation, Santa Clara University; Department of Chemistry, Santa Clara UniversityThe geometries and harmonic vibrational frequencies for the structural isomers of $CN_{2}$ and the corresponding cations have been calculated at the $B3LYP/6-311+g(2df)$ level. Adiabatic ionization energies were calculated at the G1, G2(MP2) and G2 levels as well for each of the isomers. Of the cations, the linear molecule $CNN^{+}$ is found to have the lowest energy. $NCN^{+}$ (also linear) lies 0.2 eV higher in energy than $CNN^{+}$. The other isomer of the cation, cyc-$CN_{2}^{+}$, has a cyclic structure with $C_{2v}$ symmetry and lies 0.8 eV higher in energy than $CNN^{+}$. The adiabatic ionization energies of the radicals determined at the G2 level are $IP(NCN) = 12.52 \pm 0.07 eV$, $IP(CNN) = 11.01 \pm 0.07 eV$ and $IP(cyc-CN_{2}) = 11.94 \pm 0.07 eV$