Optical-Model Analysis of 50- and 64-MeV Alpha-Particle Scattering fromNi58andFe58

An optical-model analysis of the scattering of 64.3-MeV $\alpha$ particles from ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$ and ${}_{}{}^{58}{}_{}{}^{}\mathrm{Fe}$, and of 50.2-MeV $\alpha$ particles from ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$, has been performed using independent real- and imaginary-potential-geometry parameters. The scattering is found to be sensitive only to the potential form at radial distances beyond about 6 F. Real-potential-parameter ambiguities have been studied with particular reference to the quality of the analyzed data. The potentials found are compared with expectations based upon a simple folding of matter sizes and effective two-body forces.