Generalized expressions for resonant excitation transfer and retarded dispersion energy shifts obtained using multipolar quantum electrodynamics



Generalized expressions are presented within the framework of molecular quantum electrodynamics for intermolecular interactions arising from the exchange of one or two virtual photons. When one species is excited while the other is in the ground state, the former process corresponds to resonant transfer of excitation. The rate of energy exchange for molecules possessing electric multipole moments of arbitrary order is given in terms of the resonant multipole–multipole coupling tensor. This latter quantity is then used in the calculation of the generalized dispersion energy shift between a pair of ground-state electric multipole polarizable molecules of arbitrary order via the interaction of induced multipole moments at each center. The results obtained offer an efficient alternative means of calculating higher multipole contributions to intermolecular processes. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005