Quadratic coupling in exciton–phonon interaction

Vibrationally induced exciton decay is studied theoretically. The interaction of excited and ground electronic states is quadratic in a vibrational displacement. The dissipation of the energy of the exciton–vibrational system is influenced by the coupling of a vibrational mode to a bath with a short memory function. The results of the time dependence of the exciton occurrence probability of the quadratic coupling model are discussed with respect to the parameters of the model and compared with those for the linear coupling one.