Theoretical Interpretation of the Optical and Electron Scattering Spectra of Polyatomic Molecules. III. N2O and the Discovery of Resonant Phenomena in the B Region at 6.8 eV

Abstract

Energies and parts of potential surfaces are calculated for the first eleven excited electronic states of nitrous oxide; the states within ten electron volts of the ground state. The assignment of the energies and symmetries of these states which is carried out with the aid of semiempirical INDO calculations, is shown to be consistent with all available optical absorption spectra, electron scattering data, and with photolysis and photosensitization experiments. The weak, diffuse vibrational bands in the 6.8 eV B region have been interpreted as resonant interaction between the continuum levels of the 1 ¹II state and bound vibrational levels of the underlying ¹Σ⁻ state. The mixing is made electronically allowed through bending in the excited states. Supporting experimental and theoretical evidence for this assignment are given, and experiments are suggested to confirm several of the other assignments made.