Systematic study of the surface properties of the nuclear potential with high precision large-angle quasi-elastic scatterings

High precision excitation functions of large-angle quasi-elastic scattering for the systems of ¹⁶O+²⁰⁸Pb, ¹⁹⁶Pt, ¹⁸⁴W, and ^154,152Sm at energies well below the Coulomb barrier were measured. The surface diffuseness parameters of the real part of the Woods-Saxon potential have been extracted from the single-channel and coupled-channels calculations, respectively. By considering the effect of couplings, the extracted diffuseness parameters are in the range from 0.64 to 0.69 fm, which is close to the values extracted from the systematic analyses of elastic and inelastic scattering data. On the other hand, single-channel calculations give somewhat larger values in the range from 0.68 to 0.77 fm, especially for systems with deformed target nuclei.