A potential deduced from low energy O16(α,α) elastic scattering

The properties of the α+16O interaction in the vicinity of the Coulomb barrier are investigated by constructing (real, energy-independent) potentials which reproduce-when resonant nonpotential contributions are added to the potential background-all available O16(α,α) elastic scattering angular distributions and excitation functions between 3.5 and 9 MeV incident energies. These low energy potentials, which are constructed for angular momenta ranging from 0 to 5, are in line with the global potential extracted from the analysis of the higher energy data (20≤Eα≤150 MeV), but a slight angular momentum dependence, and an increase of the barrier height of about 1 MeV, are found necessary to reproduce the low energy data; this effect is qualitatively similar to that predicted by calculations taking into account antisymmetrization or dispersion relation effects. These potentials reproduce the properties of the first three members of the Ne20 Kπ=04+ ''higher nodal'' rotational band, which dominate the scattering in the investigated energy range, and of the Jπ=5- member of the Kπ=0- ''inversion doublet'' band. By taking into account the energy dependence of the interaction at lower energy, these potentials also give a nice account of the properties of the Jπ=1- and 3- members of the same band, and are found to be compatible with the properties of the first three members of the Ne20 ground state band. © 1995 The American Physical Society.SCOPUS: ar.j