Optical-Model Analysis of Elastic Scattering of Protons on Oxygen at Intermediate Energies

Differential cross sections and polarizations for the elastic scattering of protons by oxygen at bombarding energies between 8.66 and 19.2 MeV have been analyzed using the diffuse-surface optical model of the nucleus. The best fits to the experimental data were obtained by a least-squares procedure. Excellent fits to the experimental differential cross sections were obtained over almost the entire region, although resonance structures in the cross sections required a rapid variation of the parameters with energy. The presence of a thin absorptive shell and small volume absorption is the outstanding feature of the optical potential. A Thomas spin-orbit term did not satisfactorily reproduce the experimental polarizations.