SCF Determination of the Ground and Excited States of NO2

LCAO–MO–SCF wavefunctions have been determined for the ground and five excited states of NO₂ at five different ONO angles. Molecular electronic configurations for the $\mathrm{X̃,\; Ã,}\mathrm{and}\mathrm{B̃}$ states have been assigned on the basis of the calculated vertical excitation energies and speculations for those of the $\mathrm{C̃,\; D,\; G,\; Ĩ,}\mathrm{and}\mathrm{J̃}$ states are made. The $\mathrm{G̃}$ state is predicted to be ${}^2{B}_1$ with a smaller equilibrium angle and considerably different value of $R$ from the ground state. Estimates of correlation energy changes suggest that they are probably unimportant for most of the NO₂ spectrum. The qualitative changes in orbital one‐electron energies with angle agree with those reported by others for AB₂ systems. Two closely related interpretations of geometry changes upon excitation are given, one based upon population analyses, the other on the AB₂ correlation diagram.