Towards exotic nuclei via binary reaction mechanism

Assuming a binary reaction mechanism, the yield of isotopes near the heaviest $N=Z$ neutron-deficit nucleus $^{100}$Sn is studied with a microscopic transport model. The large influence of nuclear shell structure and isotope composition of the colliding nuclei on the production of exotic nuclei is demonstrated. It is shown that the reaction $^{54}$Fe+$^{106}$Cd seems to be most favourable for producing primary exotic Sn isotopes which may survive if the excitation energy in the entrance reaction channel is less than about 100 MeV. In the case of large differences in the charge (mass) numbers between entrance and exit channels the light fragment yield is essentially fed from the decay of excited primary heavier fragments. The existence of optimal energies for the production of some oxygen isotopes in the binary mechanism is demonstrated for the $^{32}$S+$^{197}$Au reaction.Comment: 17 pages, RevTex, 8 Postscript figures, submitted to Phys. Rev.

Friction Coefficient for Deep-Inelastic Heavy-Ion Collisions

Based on the microscopic model, the friction coefficient for the relative motion of nuclei in deep-inelastic heavy-ion collisions is calculated. The radial dependence of the friction coefficient is studied and the results are compared with those found by other methods. Based on this result, it was demonstrated that the kinetic energy dissipation in deep-inelastic heavy-ion collisions is a gradual process which takes up a significant part of a reaction time. An advantage of the suggested method is that it allows one to consider the relative motion of nuclei and the intrinsic motion self-consistently.Comment: 15 pages, RevTex, 7 Postscript figures, submitted to Phys. Rev.

Polarization of the nuclear surface in deformed nuclei

The density profiles of around 750 nuclei are analyzed using the Skyrme energy density functional theory. Among them, more than 350 nuclei are found to be deformed. In addition to rather standard properties of the density, we report a non-trivial behavior of the nuclear diffuseness as the system becomes more and more deformed. Besides the geometric effects expected in rigid body, the diffuseness acquires a rather complex behavior leading to a reduction of the diffuseness along the main axis of deformation simultaneously with an increase of the diffuseness along the other axis. The possible isospin dependence of this polarization is studied. This effect, that is systematically seen in medium- and heavy-nuclei, can affect the nuclear dynamical properties. A quantitative example is given with the fusion barrier in the $^{40}$Ca+ $^{238}$U reaction.Comment: 8 pages, 13 figure

Non-Markovian dynamics with fermions

Employing the quadratic fermionic Hamiltonians for the collective and internal subsystems with a linear coupling, we studied the role of fermionic statistics on the dynamics of the collective motion. The transport coefficients are discussed as well as the associated fluctuation-dissipation relation. Due to different nature of the particles, the path to equilibrium is slightly affected. However, in the weak coupling regime, the time-scale for approaching equilibrium is found to be globally unchanged. The Pauli-blocking effect can modify the usual picture in open quantum system. In some limits, contrary to boson, this effect can strongly hinder the influence of the bath by blocking the interacting channels.Comment: 13 pages, 6 figures. Submitted to PR

Neutron pair transfer in sub-barrier capture process

The sub-barrier capture reactions following the neutron pair transfer are proposed to be used for the indirect study of neutron-neutron correlation in the surface region of nucleus. The strong effect of the dineutron-like clusters transfer stemming from the surface of magic and non-magic nuclei $^{18}$O, $^{48}$Ca, $^{64}$Ni, $^{94,96}$Mo, $^{100,102,104}$Ru, $^{104,106,108}$Pd, and $^{112,114,116,118,120,124,132}$Sn is demonstrated. The dominance of two-neutron transfer channel at the vicinity of the Coulomb barrier is further supported by time-dependent mean-field approaches.Comment: 17 pages, 7 figures, accepted in PR

Effects of nuclear deformation and neutron transfer in capture process, and origin of fusion hindrance at deep sub-barrier energies

The roles of nuclear deformation and neutron transfer in sub-barrier capture process are studied within the quantum diffusion approach. The change of the deformations of colliding nuclei with neutron exchange can crucially influence the sub-barrier fusion. The comparison of the calculated capture cross section and the measured fusion cross section in various reactions at extreme sub- barrier energies gives us information about the fusion and quasifission.Comment: 11 pages, 19 figures, submitted to Phys.Rev.