Analysis of isospin dependence of nuclear collective flow in an isospin-dependent quantum molecular dynamics model

Abstract

Within the framework of an isospin-dependent quantum molecular dynamics model in which the initial neutron and proton densities are sampled according to the densities calculated from the Skyrme-Hartree-Fock method and the initial Fermi momenta of neutrons and protons are calculated from the Fermi gas model, we study systematically the transverse collective flow of different fragment types at an energy of 55 MeV/nucleon and the balance energy in the reactions ${}^{58}\mathrm{Fe}{+}^{58}\mathrm{Fe}$ and ${}^{58}\mathrm{Ni}{+}^{58}\mathrm{Ni}.$ The results from the present calculations indicate that the neutron-rich system ${(}^{58}\mathrm{Fe}{+}^{58}\mathrm{Fe})$ displays stronger negative deflection and has a higher balance energy, which are qualitatively in agreement with the experimental data. Furthermore, the effects of the isospin-dependent symmetry energy and nucleon-nucleon cross sections on collective flow are studied.