Multinucleon transfer dynamics in heavy-ion collisions near Coulomb-barrier energies

Multinucleon transfer reactions near barrier energies have been investigated with a multistep model based on the dinuclear system (DNS) concept, in which the capture of two colliding nuclei, the transfer dynamics, and the deexcitation process of primary fragments are described by an analytical formula, diffusion theory, and a statistical model, respectively. The nucleon transfer takes place after forming the DNS and is coupled to the dissipation of relative motion energy and angular momentum by solving a set of microscopically derived master equations within the potential energy surface. Specific reactions of Ca-40,Ca-48 + Sn-124, Ca-40(Ar-40, Ni-58) + Th-232, Ca-40(Ni-58) + U-238, and Ca-40,Ca-48(Ni-58) + Cm-248 near barrier energies are investigated. It is found that fragments are produced by multinucleon transfer reactions with maximal yields along the beta-stability line. The isospin relaxation is particularly significant in the process of fragment formation. The incident energy dependence of heavy target-like fragments in the reaction of Ni-58 + Cm-248 is analyzed thoroughly.