Electronic Interaction in the Free-Electron Network Model for Conjugated Systems. II. Spectra of Aromatic Hydrocarbons

A theoretical calculation is presented for the main uv transitions of the polyacenes, azulene, phenanthrene, the isomers of naphthacene and the peri-condensed systems pyrene and coronene. A configuration interaction treatment, based on antisymmetrized products of free-electron molecular orbitals, is carried out, using the methods developed for this purpose in the previous paper. Transition energies, intensities and polarizations compare well with experiment. Particular emphasis is placed upon illuminating the various factors influencing the spectra in the series of molecules considered.