Fusion and Quasi-elastic scattering around the Coulomb barrier: determination of inter-nucleus potential

We invert experimental data for heavy-ion fusion cross sections at energies well below the Coulomb barrier in order to directly determine the internucleus potential between the colliding nuclei. In contrast to the previous applications of the inversion formula, we explicitly take into account the effect of channel couplings on fusion reactions, by assuming that fusion cross sections at deep subbarrier energies are governed by the lowest barrier in the barrier distribution. The surface region of the internuclear potential is determined from quasi-elastic scattering at deep subbarrier energies, while the inner art is determined with the WKB formula. We apply this procedure to the O-16+Sm-144 and O-16+Pb-208 reactions, and find that the inverted internucleus potential are much thicker than phenomenological potentials.