Triplet Charge Transfer Excitons in Linear Donor-Acceptor Stack

In the paper the properties of Triplet Charge Transfer Excitons (TCTEs) in a linear stack with inversion of Donor and Acceptor (DA) molecules are analyzed.On the basis of two-electron approximation and spin Hamiltonian, the expressions for transfer parameters and energy levels of the three branches of TCTEs are calculated.The dispersion and the width of the excitonic bands are obtained.The vibronic spectra of TCTEs with intramolecular phonons are studied using vibronic approach.The coupling of TCTEs with triplet Frenkel excitons is described.The model of TCTEs in DA media confirms their weak coupling with other electronic excitations and can be useful in applications connected with their big relaxation time.