Multinucleon exchange in quasifission reactions

Abstract

Nucleon exchange mechanism is investigated in the central collisions of 40 Ca + 238 U and 48 Ca + 238 U systems near the quasi-fission regime in the framework of the Stochastic Mean-Field (SMF) approach. Sufficiently below the fusion barrier, di-nuclear structure in the collisions is maintained to a large extend. Consequently, it is possible to describe nucleon exchange as a diffusion process familiar from deep-inelastic collisions. Diffusion coefficients for proton and neutron exchange are determined from the microscopic basis of the SMF approach in the semi-classical framework. Calculations show that after a fast charge equilibration the system drifts toward symmetry over a very long interaction time. Large dispersions of proton and neutron distributions of the produced fragments indicate that diffusion mechanism may help to populate heavy trans-uranium elements near the quasi-fission regime in these collisions.

TDHF Theory and Its Extensions for the Multinucleon Transfer Reaction: A Mini Review

“…An important message here is that those IQF processes emerge as a main reaction outcome in TDHF. Since larger effects of fluctuations and correlations, that give rise to a wider fragment mass distribution, are expected in such damped collisions [106,[141][142][143], novel IQF processes may pave new pathways to unexplored territories in the nuclear chart far away from the stability.…”

Multinucleon transfer in central collisions of U238+U238

“…The effects of two-body dissipation on reactions of heavy systems using the TDDM [38,39], approach have also been recently reported [40,41]. Here we discuss some recent results using the SMF method [42].…”

“…The initial conditions of the single-particle density matrices associated with the ensemble Slater determinants are specified in terms of the quantal and thermal fluctuations of the initial state. For a detailed description of the SMF approach, we refer to [37,[42][43][44]. In extracting transport coefficients for nucleon exchange, we take the proton and neutron numbers of projectile-like fragments Z λ 1 , N λ 1 as independent variables, where λ indicates the event label.…”

“…In a number of studies, it has been demonstrated that the SMF approach is a good remedy for this shortcoming of the mean-field approach * ayik@tntech.edu and improves the description of the collisions dynamics by including fluctuation mechanism of the collective motion [42][43][44][45]. Most applications have been carried out in collisions where a di-nuclear structure is maintained.…”

Quantal nucleon diffusion: Central collisions of symmetric nuclei

“…In a number of studies, it has been demonstrated that the SMF approach alleviates the drawbacks of the standard mean-field approach and improves the description of nuclear collisions dynamics including fluctuation mechanism of the collective motion [30,[32][33][34][35][36][37]. Most applications have been carried out for collisions where a di-nuclear structure is maintained.…”