Electronic Spectra of Quinoline and Isoquinoline and the Mechanism of Fluorescence Quenching in These Molecules

Abstract 1. A pertubation theory based on the Hartree-Fock SCF theory including a limited number of configuration interactions was applied to quinoline and isoquinoline. 2. The theory satisfactorily interprets the excitation energies and oscillator strengths of 1Lb bands of these nitrogen heterocycles. 3. The previous assumption concerning the effect of π-electronic state on the fluorescence quenching in nitrogen heterocycles due to the near-by existence of a halogen atom, was confirmed for the case of quinoline, on the basis of the theoretical calculation.