Retarded intermolecular interactions involving diamagnetic molecules

Second- and third-order time-dependent perturbation theory within the multipolar framework of nonrelativistic quantum electrodynamics is used to calculate the retarded dispersion interaction between two diamagnetic molecules, a diamagnetic molecule and a magnetic-dipole susceptible molecule, and a diamagnetic molecule and an electric-quadrupole polarizable molecule. New expressions for the energy shift valid for all intermolecular separation distances, R, beyond the region of overlap of molecular electronic wave functions and applicable to a pair of randomly oriented molecules in the ground electronic state are given. The R-dependent behavior of the far-zone limit of the interaction energies is also examined. (C) 2000 John Wiley & Sons, Inc.