Polarization effect in the electronically excited state of benzene derivatives and related compounds

The energies of intramolecular charge-transfer bands and excited singlet and triplet states, as well as the molar absorption coefficients of mono- and para-disubstituted benzenes and monosubstituted naphthalenes and pyridines depend not only on the inductive and resonance substituent effects, but also on their polarization effect which can be characterized by sigma(alpha) constants. The polarization effect determines the lifetime of the triplet state and phosphorescence quantum yield of monosubstituted naphthalenes.