Electronic Structure and Electronic Spectrum of Nitrogen Dioxide. II. Configuration Interaction and Oscillator Strengths

Abstract

The ground state and the five lowest excited states of NO2 which were investigated in an earlier work are studied further. It is found that, of various methods of including configuration interaction, better results are obtained when configurations of each symmetry and spin species are formed from the self-consistent field orbitals of the lowest state of that species. With a basis set of 33 Gaussian-type orbitals, up to 180 configurations are included at three values of the bond angle to obtain potential-energy curves of the six states. The calculations are then repeated at the equilibrium geometry of the gound state using 72 Gaussian-type orbitals contracted to 39 basis functions. Oscillator strengths of the allowed and forbidden transitions are obtained.