Phonon-Induced Exciton Interactions

Abstract

Second‐order perturbation theory is used to calculate the effective exciton—exciton interaction potential resulting from a first‐order exciton—phonon coupling in a linear chain of ``diatomic'' molecules. The calculations imply that the virtual exchange of acoustic phonons leads to an attractive interaction while virtual exchange of optical phonons tends to cause a repulsive potential. The two limiting cases of strongly and weakly bound dimers are investigated and are used to suggest that the phonon‐induced interaction potential in the systems of interest is probably attractive.