Surface transparency of optical potentials deduced from heavy-ion scattering studies

Abstract

The elastic and inelastic cross-sections of 16,18O and 12C scattered from targets of even-even Ge and Ni isotopes have been measured over an angular range 12.5°–100° (laboratory angle) at E 16,180 = 56 MeV and E 12C = 48 MeV. By simultaneously fitting the angular distributions for the ground state (0 +) and first-excited level (2 +) using a coupled-equations search routine, we have been able to determine the optical potential parameters almost uniquely. The optical potentials so obtained exhibit two characteristic features: (1) the well depth of the imaginary part of the potential is larger than the well depth of the real part and (2) the radius and diffuseness of the imaginary part are respectively smaller than those of the real part. In addition, the deflection function corresponding to such surface transparent potentials displays a significant minimum at the grazing angular momentum.