Semi-Empirical Configuration Interaction Studies on the π-Electron Spectra of Nonbenzenoid Molecules

A modification of the method of Yamaguchi et al. has been used to predict the π-electronic spectra of a number of nonbenzenoid molecules containing five- and seven-membered rings. Good correlation of the theoretical and experimental transition energies is found. The calculated intensities are also reasonably consistent with experiment, to the extent of raising questions as to the source of intensity in the bands of some molecules.