Time-dependent Hartree-Fock calculations for multinucleon transfer and quasifission processes in theNi64+U238reaction

Abstract

Background: Multinucleon transfer (MNT) and quasifission (QF) processes are dominant processes in lowenergy collisions of two heavy nuclei. They are expected to be useful to produce neutron-rich unstable nuclei. Nuclear dynamics leading to these processes depends sensitively on nuclear properties such as deformation and shell structure.Purpose: We elucidate reaction mechanisms of MNT and QF processes involving heavy deformed nuclei, making detailed comparisons between microscopic time-dependent Hartree-Fock (TDHF) calculations and measurements for the 64 Ni+ 238 U reaction.Methods: Three-dimensional Skyrme-TDHF calculations are performed. Particle-number projection method is used to evaluate MNT cross sections from the TDHF wave function after collision.Results: Fragment masses, total kinetic energy (TKE), scattering angle, contact time, and MNT cross sections are investigated for the 64 Ni+ 238 U reaction. They show reasonable agreements with measurements. At small impact parameters, collision dynamics depends sensitively on the orientation of deformed 238 U. In tip (side) collisions, we find a larger (smaller) TKE and a shorter (longer) contact time. In tip collisions, we find a strong influence of quantum shells around 208 Pb.Conclusions: It is confirmed that the TDHF calculations reasonably describe both MNT and QF processes in the 64 Ni+ 238 U reaction. Analyses of this system indicate the significance of the nuclear structure effects such as deformation and quantum shells in nuclear reaction dynamics at low energies.

Exploring Zeptosecond Quantum Equilibration Dynamics: From Deep-Inelastic to Fusion-Fission Outcomes in Ni58+Ni60Williams1, Sekizawa2, Hinde3 et al. 2018Phys. Rev. Lett.475550View full textAdd to dashboardCite

“…, TKE) and impact parameter b, and to examine the origin of the wide mass ratio component, microscopic approaches TDHF and TDRPA have been used. TDHF is a mean-field approach incorporating onebody dissipation that has previously been used to explore dynamical reaction processes such as quasifission [10,[24][25][26][27][28][29][30]. In this work, a 3D TDHF code [31,32], employing the SLy4d parametrization [33] of the Skyrme energydensity functional [34] has been used to explore reaction outcomes for 58,60 Ni+ 60 Ni at the three representative energies shown in Fig.…”

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

“…Recent investigations have also shown that the one-body dissipation mechanisms included in TDHF were the most relevant to describe fully damped reactions such as quasi-fission [55][56][57][58][59][60]. In this manuscript we study various aspects of deep-inelastic collisions using the TDHF approach.…”

Multinucleon transfer in central collisions of U238+U238

“…It is also possible to compute the probability to form a fragment with a given number of nucleons [27][28][29][30][31][32], but the resulting fragment mass and charge distributions are often underestimated in dissipative collisions [33,34]. Much effort has been done to improve the standard mean-field approximation by incorporating the fluctuation mechanism into the description.…”

“…A number of models was developed for a description of the reaction mechanism in the multi-nucleon transfer process in quasi-fission reactions [1][2][3][4]. Within the last few years the time-dependent Hartree-Fock (TDHF) approach [5][6][7] has been utilized for studying the dynamics of quasifission [7][8][9][10][11][12][13][14][15][16][17] and scission dynamics [18][19][20][21][22][23]. Such calculations are now numerically feasible to perform on a 3D Cartesian grid without any symmetry restrictions and with much more accurate numerical methods [24][25][26].…”