TDHF and a Macroscopic Aspect of Low-Energy Nuclear Reactions

Washiyama, Kouhei; Sekizawa, Kazuyuki

doi:10.3389/fphy.2020.00093

Cited by 9 publications

(3 citation statements)

References 53 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…TDHF calculations, on the other hand, account for such rearrangement, at the mean-field level, in particular those produced by couplings to vibrational [51,67,68] and rotational modes [69,70], as well as nucleon transfer through the neck [48,50,[71][72][73][74][75]. Nucleus-nucleus potentials extracted from TDHF calculations [47,49,52,76] then account for both dynamical effects as well as the Pauli exclusion principle. In order to further investigate the full dynamics we have thus used the DC-TDHF method, where the densities are taken directly from the TDHF evolution of the system and the same constraint procedure used in DCFHF is employed (see [52] for details):…”

Section: A Microscopic Methodsmentioning

confidence: 99%

Pauli energy contribution to nucleus-nucleus interaction

Umar,

Simenel,

Godbey

2021

Preprint

View full text Add to dashboard Cite

Background: The Pauli exclusion principle plays a crucial role as a building block of many-body quantal systems comprised of fermions. It also induces a "Pauli repulsion" in the interaction between di-nuclear systems. It has been shown in [Phys. Rev. C95, 031601 (2017)] that the Pauli repulsion widens the nucleus-nucleus potential barrier, thus hindering sub-barrier fusion. Purpose: To investigate the proton and neutron contributions to the Pauli repulsion, both in the bare potential neglecting shape polarization and transfer between the reactants, as well as in the dynamical potential obtained by accounting for such dynamical rearrangements. Methods: As the basis of our study we utilize the Pauli kinetic energy (PKE) obtained by studying the nuclear localization function (NLF). Recently this approach has been generalized to incorporate all of the dynamical and time-odd terms present in the nuclear energy density functional. This approach is employed in the density constrained Hartree-Fock (DCFHF) and in the density constrained time-dependent Hartree-Fock (DC-TDHF) microscopic methods. Results: The PKE spatial distribution shows that a repulsion occurs in the neck between the nuclei when they first touch. Inside the barrier, neutrons can contribute significantly more to the Pauli repulsion in neutron-rich systems. Dynamical effects tend to lower the Pauli repulsion near the barrier. Proton and neutron dynamical contributions to the PKE significantly differ inside the barrier for asymmetric collisions, which is interpreted as an effect of multinucleon transfer. Conclusions: The PKE is shown to make a significant contribution to nuclear interaction potentials. Protons and neutrons can play very different roles in both the bare potential and in the dynamical rearrangement. Further microscopic studies are required to better understand the role of transfer and to investigate the effect of pairing and deformation.

show abstract

Section: A Microscopic Methodsmentioning

confidence: 99%

Pauli energy contribution to nucleus-nucleus interaction

Umar,

Simenel,

Godbey

2021

Preprint

View full text Add to dashboard Cite

show abstract

“…A threedimensional parallel TDHF solver was used, which has been continuously developed since the work by Sekizawa and Yabana [50]. The code has been successfully applied for a number of systems [5,11,[50][51][52][53][54], including various extensions going beyond TDHF [55][56][57][58]. In our preceding studies, we FIG.…”

Section: Tdhf Analysismentioning

confidence: 99%

Reaction mechanism study for multinucleon transfer processes in collisions of spherical and deformed nuclei at energies near and above the Coulomb barrier: The $^{16}$O+$^{154}$Sm reaction

Roy,

Santra,

Pal

et al. 2021

Preprint

View full text Add to dashboard Cite

Background: Multinucleon transfer reactions at energies around the Coulomb barrier offer a vital opportunity to study rich physics of nuclear structure and dynamics, e.g., single-particle level structure and quantum shells, mass/charge equilibration processes, energy dissipation, as well as secondary decays via particle emission or fission. Despite the continuous development in the field, we have still limited knowledge about how deformation-one of the representative nuclear structures-affects multinucleon transfer reactions.Purpose: To shed light on the effect of deformation in multinucleon transfer processes, we study the 16 O+ 154 Sm reaction at E lab = 85 MeV (around the Coulomb barrier) and 134 MeV (substantially above the Coulomb barrier), where the target nucleus, 154 Sm, is a well-established, deformed nucleus. Methods:We have performed experiments on the 16 O+ 154 Sm reaction at the BARC-TIFR pelletron-Linac accelerator facility, Mumbai, India, measuring angular distributions for various transfer products. The measured cross sections have been analyzed along with theoretical calculations based on the time-dependent Hartree-Fock (TDHF) theory, together with a statistical model for secondary deexcitation processes, GEMINI++.Results: Angular distributions for elastic scattering and for various transfer channels were measured over a wide angular range. The Q-valueand angle-integrated isotope production cross sections have been extracted from the measured angular distributions. We have successfully obtained production cross sections for various isotopes for E lab = 85 MeV, while only for four isotopes could be deduced for E lab = 134 MeV due to present experimental limitations. For the lower incident energy case, we find a reasonable agreement between the measurements and the TDHF calculations for a-few-nucleon transfer channels; whereas TDHF underestimates cross sections for many-nucleon transfers, consistent with earlier works. On the other side, we find that calculated cross sections for secondary reaction products for the higher incident energy case, qualitatively explains the measured trends of isotopic distributions observed for the lower energy. The latter observation indicates possible underestimation of excitation energies in the present TDHF+GEMINI analysis. Although certain orientation effects were observed in TDHF results, it is difficult to disentangle them from the Q-valueand angle-integrated production cross sections. Conclusions:The present analysis showed that the orientation effect in multinucleon transfer processes in the 16 O+ 154 Sm reaction is rather weak at least for the two incident energies examined. Further systematic investigations with carefully changing projectile-target combinations and collision energies, including subbarrier regime, would be required to fully uncover the effects of nuclear deformation on multinucleon transfer processes in low-energy heavy-ion reactions.

show abstract

“…The semiclassical models, such as the dinuclear system (DNS) model [51][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66], the Langevin equations [67][68][69][70], the GRAZING model [40,[71][72][73][74][75], and the complex Wentzel-Kramers-Brillouin model [76][77][78]. The microscopic dynamics models, such as the improved quantum molecular dynamics (ImQMD) model [79][80][81][82][83][84] and the time-dependent Hartree-Fock model [85][86][87][88][89][90][91][92][93][94][95][96][97][98]…”

Section: Introductionmentioning

confidence: 99%

Production mechanism and prediction cross sections of unknown neutron-rich ^{263–265,267–269}Lr isotopes in multinucleon transfer reactions based on the dinuclear system model

Zhang¹,

Zhang²,

Li³

et al. 2022

J. Phys. G: Nucl. Part. Phys.

View full text Add to dashboard Cite

Within the framework of the dinuclear system model, the production cross sections for producing the new neutron-rich Lr isotopes in the multinucleon transfer reactions with 249Bk and 254Es targets were predicted. The results show that the 124Sn+254Es reaction has the highest production cross sections, followed by the 130Te+249Bk reaction. As far as the existing experimental techniques are concerned, 130Te+249Bk is the most suitable choice. With experimental techniques developing in the future, 124Sn+254Es is preferable when the thick 254Es target can be prepared. The optimal energy for producing the new neutron-rich Lr isotopes is 1.1 times the Coulomb barrier for both reaction systems, and both reactions produced 263-265,267-269Lr isotopes. The production mechanism of Lr isotopes has been investigated in the 130Te+249Bk reaction. It is found that the production of Lr isotopes mainly originates from the contribution of quasiﬁssion. And the contribution of quasiﬁssion gradually decreases with the increase of the incident angular momentum. The ﬁnal production cross sections for 263-265,267-269Lr in 130Te+249Bk reaction at Ec.m.=1.10VC are 0.22 µb, 0.13 µb, 0.15 µb, 4.45 nb, 0.62 nb, and 0.03 nb, respectively.

show abstract

TDHF and a Macroscopic Aspect of Low-Energy Nuclear Reactions

Cited by 9 publications

References 53 publications

Pauli energy contribution to nucleus-nucleus interaction

Pauli energy contribution to nucleus-nucleus interaction

Reaction mechanism study for multinucleon transfer processes in collisions of spherical and deformed nuclei at energies near and above the Coulomb barrier: The $^{16}$O+$^{154}$Sm reaction

Production mechanism and prediction cross sections of unknown neutron-rich ^{263–265,267–269}Lr isotopes in multinucleon transfer reactions based on the dinuclear system model

Contact Info

Product

Resources

About

TDHF and a Macroscopic Aspect of Low-Energy Nuclear Reactions

Cited by 9 publications

References 53 publications

Pauli energy contribution to nucleus-nucleus interaction

Pauli energy contribution to nucleus-nucleus interaction

Reaction mechanism study for multinucleon transfer processes in collisions of spherical and deformed nuclei at energies near and above the Coulomb barrier: The $^{16}$O+$^{154}$Sm reaction

Production mechanism and prediction cross sections of unknown neutron-rich 263–265,267–269Lr isotopes in multinucleon transfer reactions based on the dinuclear system model

Contact Info

Product

Resources

About

Production mechanism and prediction cross sections of unknown neutron-rich ^{263–265,267–269}Lr isotopes in multinucleon transfer reactions based on the dinuclear system model