The phosphorescence blue shift of anthracene in a charge transfer configuration: A consequence of the donor acceptor overlap in anthracene-PMDA crystals

Abstract

A 500 cm-1 blue shift of the phosphorescence origin of anthracene in anthracene-PMDA single crystals has been measured. Calculations based on a perturbation theory approach show that the symmetry of the highest occupied and lowest unoccupied orbitals of the anthracene and PMDA molecule, together with the specific geometry of a charge transfer complex, are responsible for the observed shift. The simple model yields the surprising result that the energy of the excited triplet state is less affected by the interaction with a charge transfer state than the energy of the ground state. Copyright © 1977 American Institute of Physics.