INTERMOLECULAR ENERGY SHIFTS BETWEEN 2 CHIRAL MOLECULES IN EXCITED ELECTRONIC STATES

Higher order multipole contributions to the energy shift between two n eutral polarizable molecules in excited electronic states are calculat ed using molecular response theory within the formalism of non-relativ istic quantum electrodynamics. The interaction between two electric-ma gnetic dipole polarizable molecules is discriminatory, being dependent on the chirality of each species. The energy shift between an electri c dipole polarizable molecule interacting with either a magnetic dipol e or electric quadrupole polarizable molecule is also evaluated. The p otentials obtained apply to two randomly oriented molecules and are va lid for all intermolecular separation distances outside electron overl ap. The interaction energy when one or both of the pair are in ground electronic states is easily deduced from the general result for two ex cited molecules. The limiting behaviour of the various energy shifts a t large and small separation distances is also examined.