NUCLEON-NUCLEUS OPTICAL-MODEL POTENTIAL .3. SPIN-ORBIT COMPONENT

As an extension of our earlier work, we calculate the spin-orbit part of the nucleon-nucleus optical potential (Vs.o. + Ws.o.) starting from the Hamada-Johnston internucleon potential. We find that the radial shape of Vs.o. is essentially energy independent and peaks in the nuclear surface while its strength varies only slowly with energy. The energy dependence of Ws.o. is much greater. For 20 MeV nucleons we find that Ws.o peaks appreciably further from the nuclear centre than Vs.o. and that the ratio of the potential depths is Ws.o./Vs.o. ≈ - 0.05. For 200 MeV nucleons Ws.o. and Vs.o. have the same shape and Ws.o./Vs.o. ≈ -0.2. These predictions are not readily comparable with most phenomenological analyses because the earlier give a wide divergency of results. As a preliminary test of our theory we have used our calculated spin-orbit potential to obtain polarizations and cross sections for the scattering of 30.3 MeV protons from 40Ca. We obtain good agreement with the experimental data without any parameter fitting. © 1978.