Threshold behavior of interaction potential for the system 7Li + 64Ni: Comparison with 6Li + 64Ni

Abstract

The elastic scattering angular distributions for the system 7Li + 64Ni were measured in the bombarding energy range of 12 MeV≤Elab≤26.4 MeV. A phenomenological optical model analysis was performed for the measured data. The strengths of the fitted potential components at the surface were estimated to extract their variation with energy. Further analyses of the measured angular distributions were performed with a hybrid potential composed of a renormalized folded real and a phenomenological imaginary potential. Both the model potentials predict similar energy dependent behavior for the effective interaction potential around the barrier. Unlike the heavy targets, 7Li + 64Ni does not show a normal threshold behavior. It also does not clearly exhibit a behavior similar to 6Li + 64Ni. The real potential for 7Li + 64Ni does not exhibit any significant energy dependence and the imaginary potential strength remains almost independent of energy above the Coulomb barrier (∼14 MeV). However, at energies below the barrier, a sudden drop in the imaginary potential strength is observed.