General features of nucleon-nucleus interaction in the resonating-group formulation.

Abstract

The general properties of the nucleon-nucleus interaction is studied by considering a nonlocal model, called model K, which is formulated within the framework of the resonating-group method, but with the simplifying assumptions of approximating target-recoil effects and taking into account only the knockon-exchange contribution. The procedure that we follow is to first construct and then examine the internuclear equivalent local potentials corresponding to the nonlocal interaction of model K. Two methods of construction are adopted; these are the Born approximation and the WKB procedure. From the resultant equivalent local potentials, we obtain the following interesting findings: (i) The knockon-exchange process is important especially at lower energies; for example, at 20 MeV, the volume integral of the knockon-exchange potential is equal to 29% of that of the direct potential; (ii) a proper consideration of antisymmetrization alone can already account for about 70% of the energy dependence of the empirically determined internuclear local potential; and (iii) the nucleon-nucleus interaction does not seem to depend sensitively on the excitation energy of the target nucleus.