Various Nuclear-Potential Descriptions of the Elastic Scattering ofO16+Ca40

Abstract

Excitation functions for the elastic scattering of ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ by ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ were measured in 0.5-MeV steps at c.m. angles 59.1°, 90.0°, 123.2°, and 144.13° in the energy range (lab) 23-42 MeV. At the laboratory energies 38, 40, and 42 MeV, angular distributions were obtained between 25°-130° (c.m.) in 2.5° steps. The data were analyzed using an optical-model-type calculation for various potential forms. The standard optical-model potential using a real and imaginary potential with a Woods-Saxon form factor was insufficient to yield a complete description of the data. A recent extension of the optical model to include an $l$-dependent absorption term gave a better description of the experimentally measured cross sections. The inclusion of a short-range repulsive core in the nuclear potential did not greatly alter the calculated cross sections. A semiclassical rainbow-scattering analysis was also performed in order to obtain better insight into the various optical-model parameters, and also to determine the importance of the tail region of the nuclear potential in the ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$-${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ elastic scattering.