Molecular resonance interaction in channels

A theory is presented for the retarded resonance interaction between two identical molecules in an excited configuration in channels with dielectric, or ideal metallic walls. The boundaries have a strong influence on the interaction. For dielectric walls this is illustrated numerically, for metallic walls analytically. Near a single metallic surface and in free space the long-range retarded interaction is proportional to 1/rho(4). At the mid-plane of a narrow cavity with conducting walls it decays more slowly being proportional to 1/rho(3). In a cavity the interaction can change from a long-range attraction to short-ranged repulsion. This circumstance gives rise to bound states wherein molecules can be trapped, while energy is transferred between the molecules.