Molecular Orbital Studies on Electronic Spectra of Some Substituted Anthraquinone Cation Radicals

Abstract

Electronic transition energies of radical cations of some hydroxy-substituted anthraquinones are calculated using an open-shell self-consistent field method with limited configuration interaction. The results are analyzed and a correlation diagram is given which provides useful information about the characteristic behaviour of the electronic transitions depending on the positions of the hydroxyl substituents. Also, the first ionization potentials of substituted anthraquinones are calculated using an empirical relation connecting ionization potentials with the lowest-energy non-Koopmans bands for their radical cations. Such information is particularly useful for systems like substituted anthraquinones for which uv photoelectron spectroscopic data are in scarce.