A Semi-empirical Theory of the π-Electronic Spectra of Aromatic Derivatives

A semi-empirical theory of the π-electronic spectra of aromatic derivatives based on anti symmetrized molecular orbital method is given and is applied to the calculations of the singlet π-electronic states of hydroquinone and of phloroglucinol. In the theory the core integrals over AO’s of heteroatoms are expressed as the functions of the core integrals over carbon atom 2pπ AO’s. The calculated excitation energies for these molecules agree satisfactorily with the observed ones. In addition, our calculations give some informations with respect to the nature of their electronic state and their first ionization potentials.