Quantum mechanical calculation of vibronic effects on the S 2S 0 transition of azulene

Abstract

The a 1 adiabatic normal coordinates of the states S o and S 2 have been computed by the QCFF/PI program. The associated Duschinsky effect has been shown to result from vibronic perturbations of the state S 2. This conclusion is confirmed by CNDO/S calculations which show that vibronic coupling between S 2 and S 4 plays a fundamnetal role. Computed vibronic intensities for absorption and fluorescence agree satisfactorily with observed intensities and describe correctly the fluorescence—absorption mirror-symmetry breakdown.