The ²⁰Ne(¹⁶O,¹⁶O)²⁰Ne excitation function at θ_c.m. = 90° and parity-dependent interactions

The excitation function for ¹⁶O + ²⁰Ne elastic scattering at θ_c.m. = 90° has been measured over the energy range 21.5 MeV < E_c.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 θ_c.m. = 90° and θ_c.m. = 154° ± 2° with a potential which is deeper for even than for odd partial waves. Such a parity dependence is consistent with the assumption that this term arises from 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.