An ab initio potential-energy surface study of several electronic states of NO2

Abstract

The results of ab initio potential‐energy surface calculations are presented for 12 doublet and four quartet states of NO₂. In several cases C_s as well as C_2v conformations have been studied. The predicted equilibrium conformations and the character of the wavefunctions are discussed. Vertical excitation energies are given for 40 doublet and 12 quartet states. The electronic spectrum of NO₂ is discussed, and barriers to photodissociation are estimated for several electronic states. Whether states will be strongly Jahn–Teller coupled by a symmetry‐reducing vibrational interaction depends on their potential surfaces and the character of their wavefunctions. This vibronic interaction in some cases is expected to produce non‐C_2v equilibrium conformations.