Systematic investigation of “hindrance” in heavy-ion fusion reactions at deep sub-barrier energies

Abstract

In order to explore the influence of adiabatic process on fusion reactions, we employ 13 different phenomenological nuclear potentials to make a systematic comparison of the experimental and calculated fusion cross sections. After two colliding nuclei contact, the adiabatic process is introduced to calculate the fusion cross sections at the above- and sub- barrier energies for 16 fusion reactions. At deep sub-barrier energy region, a detailed investigation is made to study the fusion hindrance by taking Krappe-Nix-Sierk, Bass (1980), and Akyüz-Winther nuclear potentials as examples. For newly observed fusion systems 12C + 198Pt, 11B + 197Au, and 40Ca + 90Zr, the calculated fusion cross sections are in good agreement with experimental data by considering the damping of coupled-channels effect. The results of astrophysical S factor and logarithmic derivative at deep sub-barrier energies show a close dependence on the behavior of potentials inside the Coulomb barrier. For newly observed light mass system 12C + 30Si, the corresponding improvement by considering the damping factor is small owing to the weak coupling effect.