Transport properties of isospin asymmetric nuclear matter using the time-dependent Hartree-Fock method

Background: The study of deep-inelastic reactions of nuclei provides a vehicle to explore nuclear transport phenomena for a full range of equilibration dynamics. These investigations provide us the ingredients to model such phenomena and help answer important questions about the nuclear equation of state and its evolution as a function of neutron-to-proton (N/Z) ratio. Purpose: The motivation is to examine the real-time dynamics of nuclear transport phenomena and its dependence on N/Z asymmetry from a microscopic point of view to avoid any pre-conceived assumptions about the involved processes. Method: The time-dependent Hartree-Fock (TDHF) method in full three dimensions is employed to calculate deep-inelastic reactions of Kr78+Pb208 and Kr92+Pb208 systems at 8.5 MeV/nucleon. The impact parameter and energy-loss dependence of relevant observables are calculated. In addition, the density-constrained TDHF method is used to compute excitation energies of the primary fragments. The statistical deexcitation code gemini is utilized to examine the final reaction products. Results: The kinetic energy loss and sticking times as a function of impact parameter are calculated. The final properties of the fragments (charge, mass, scattering angle, and kinetic energy) are computed. Their evolution as a function of energy loss is studied and various intra-relations are investigated. The fragment excitation energy sharing is computed. Conclusions: We find a smooth dependence of the energy loss, Eloss, on the impact parameter for both systems. However, the transfer properties for low Eloss values are very different for the two systems but become similar in the higher Eloss regime. The mean lifetime of the charge equilibration process, obtained from the final (N-Z)/A value of the fragments, is shown to be ∼0.5 zs. This value is slightly larger than (but of the same order as) the value obtained from reactions at Fermi energies.