Average Fluctuation Potential as Effective Interaction in Composite-System Scattering

Abstract

Symmetric forms of the effective interactions both for the elastic and rearrangement collisions of composite systems are derived, and the distorted-wave amplitudes are constructed. Explicit forms of the effective-interaction potentials contain in common a single Green's function factor as the distortion effect of the indirect channels which appear only as intermediate states. Approximation methods to evaluate this factor are discussed in terms of the closure, unitarity, and certain self-consistency requirements, while the direct channels are treated exactly. The closure approximation gives rise to the average fluctuation potentials which contain the complex average energies as adjustable parameters. Preliminary attempts to estimate these parameters theoretically are described for some special cases. The resulting approximate expressions for the amplitudes retain explicitly information on the two-body interactions and the asymptotic boundary conditions for the direct channels.