Optical model analysis of 14 to 40 MeV neutron elastic scattering from 27Al, 28Si and 32S

An optical model analysis of 14 to 40 MeV neutrons elastic scattering from 2s-1d shell nuclei 27Al, 28Si and 32S is described. A set of spherical optical model parameters is presented for each nucleus. A regional neutron optical model, valid for nuclei near the center of the 2s-1d shell, is proposed. A comparison between neutron and relevant proton data, which entailed the analysis of the latter, confirms earlier determinations of the Coulomb correction term to the real potential and of the strength of the real isospin potential. (orig.)