Theoretical excitation energies of the lowest quartet states of nitrogen dioxide

The quartet–doublet vertical transition energies of NO2 have been calculated by ab initio methods that include large-scale configuration interaction. A double-zeta quality basis set augmented with polarization functions is employed in this work. The 4B2←X 2 A1 and 4A2←X 2A1 vertical excitation energies are calculated directly and the corresponding vertical de-excitation energies are inferred from this and previous work.