Extension of the Optical Model and Its Application to the Elastic Scattering ofO16byO16Nuclei

The absorptive part of the optical potential is considered as a function of conserved quantum numbers such as the total angular momentum $J$. This investigation results in the introduction of a smooth cutoff in the strength of the absorptive potential as $J$ gets larger than a certain critical value. This value is typical of nonelastic channels, and the cutoff reflects poor matching between the angular momenta in the elastic channel and those in the nonelastic channels. Brief consideration is also given to other conserved or approximately conserved quantum numbers such as isobaric spin and parity. The standard optical potential is modified to include an angular-momentum dependence with a suitable cutoff, and is applied to the elastic scattering of ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ by ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ nuclei. In the energy range 15-36 MeV (c.m.), such an extended optical model gives a good description of all the gross features of the ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$-${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ data. A repulsive core in the ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$-${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ potential has been considered, but no definite evidence for it is found in the present analysis.