Theoretical studies of molecular ions. Vertical ionization potentials of the nitrogen molecule

The ²Σ⁺_g, ²Π_u, and ²Σ⁺_u vertical ionization energies of nitrogen are obtained by using our theory of molecular electron affinities and ionization potentials, which permits the direct calculation of the ion-molecule energy differences. The contributions of charge redistribution and correlation energy change to the calculated ionization potentials are evaluated. The computational efficiency of the method is illustrated and comparisons are made with recent experimental results.