The 20Ne(16O,16O)20Ne excitation function at θc.m. = 900 and parity-dependent interactions

The excitation function for 16O + 20Ne elastic scattering at θc.m. = 900 has been measured over the energy range 21.5 MeV < Ec.m. < 31.2 MeV and analysed within the framework of an extended optical model, in order to place additional constraints on spin assignments to resonant states, and hence constraints on the parity dependent part of the 16O-20Ne potential. A satisfactory description is obtained of elastic scattering excitation functions at θc.m. = 900 and θc.m. = 1540 ± 20 with a potential which is deeper for even tahn for odd partial waves. Such a parity dependence is consistent with the assumption that this term arises form a requirement to simulate the effects of α-transfer amplitudes, and with the expectations of models which argue that parity dependence is to be expected as a consequence of the Pauli principle. (orig.)