Probing the production mechanism of neutron-rich nuclei in multinucleon transfer reactions

Aiming at understanding the production mechanism of new neutron-rich nuclei around N = 126, the multinucleon transfer reaction Xe-136 + Pb-208 at E-c.m. = 450 MeV has been investigated in the framework of the three-dimensional time-dependent Hartree-Fock (TDHF) theory and a statistical model GEMINI. The calculated production cross sections of the targetlike fragments are compared with the experimental data. The model predictions can well describe the yields of nuclei near the target. The reactions of Sn-132 + Pb-208 at different incident energies above the Coulomb barrier are also studied. It is shown that this system is a better candidate for producing N = 126 neutron-rich nuclei than using Xe-136 as the projectile because of the favored proton pickup and neutron stripping transfer channels. The study of de-excitation effect indicates that the suitable incident energy to synthesize neutron-rich nuclei should be just above the Coulomb barrier. It is also found in Sn-132 + Pb-208 that about 50 new neutron-rich nuclei with the production cross sections larger than 10(-6) mb are obtained dominantly through quasifission and deep-inelastic collisions. However, those with N = 126 are mainly from grazing collisions. Comparison with the results of the GRAZING model is also discussed.