Comprehensive Study Of Weakly Bound Nuclear 6li +208 Of Pb Important Reaction Road

It is one of the most frontal fields of nuclear physics to study nuclear structure and reaction mechanism in extreme conditions. The halo and weakly bound nuclei have a high probability of breakup during the colliding processes, which has a strong effect on the fusion around the Coulomb barrier. But the problem is still open whether the fusion cross section would be enhanced or decreased in experiment and theory. It is also related to understand the synthesis mechanism of super-heavy elements. Since the weakly bound stable nuclear 6Li has similar characteristics with halo nuclei. We have selected the 6Li + 208Pb as the investigated object.The experiments were performed at the HI-13 tandem Van-de Graff accelerator of China Institute of Atomic Energy, Beijing. The angular distributions of elastic scattering, the fusion excitation function, the quasi-elastic scattering excitation function at backward angle, have been measured for the 6Li + 208Pb system at the near- and sub-barrier energies. We have obtained the energy-dependent potential of interaction at sensitive radius and discovered that the deformation parameter β2 of 6Li is important for the threshold anomaly. The experiment results show that the fusion cross sections are suppressed at above-barrier energies due to the effects of 6Li breakup, but the effects of breakup are not clear at below the barrier. The quasi-elastic barrier distribution Dqel (E) extends to low energy region and enhances the fusion cross section at the sub-barrier energies. It is still needed to do some work to determine the deformation parameter β2 for light odd-odd nucleus, like 6Li and to calculate all reaction channels by means of CDCC code simultaneously. It is important to measure the exclusive angular distributions of breakup fragments.In theory, the coupling channel equations have been deduced from one-dimensional to multi-dimensional barrier tunneling. The couplings between the entrance channel and the other channels have appreciableeffects on sub-barrier fusion cross section. Instead of single fusion barrier,these couplings lead to a distribution of fusion barrier Dfus (E). The barrier distributions, Dfus (E) and Dqel (E), have been derived from fusion excitation function and quasi-elastic scattering excitation function. The ECIS97 and CCFULL codes have been used to derivate sensitive radius , optical potential and calculate the fusion excitation function, respectively.