Intermolecular energy shifts between two chiral molecules in excited electronic states

Abstract

Higher order multipole contributions to the energy shift between two neutral polarizable molecules in excited electronic states are calculated using molecular response theory within the formalism of non-relativistic quantum electrodynamics. The interaction between two electric-magnetic dipole polarizable molecules is discriminatory, being dependent on the chirality of each species. The energy shift between an electric dipole polarizable molecule interacting with either a magnetic dipole or electric quadrupole polarizable molecule is also evaluated. The potentials obtained apply to two randomly oriented molecules and are valid for all intermolecular separation distances outside electron overlap. The interaction energy when one or both of the pair are in ground electronic states is easily deduced from the general result for two excited molecules. The limiting behaviour of the various energy shifts at large and small separation distances is also examined.