Energy dependence of the nucleus-nucleus potential and the friction parameter in fusion reactions

Wen, Kai; Sakata, Fumihiko; Li, Zhuxia; Wu, Xizhen; Zhang, Yingxun; Zhou, Shan‐Gui

doi:10.1103/physrevc.90.054613

Cited by 18 publications

(8 citation statements)

References 82 publications

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“…As one can see in Fig. 1, such a reaction never reaches to the shape of resulting compound nucleus in TDHF simulations because of lack of dissipation beyond the mean-field level, e.g., two-body dissipation arising from direct nucleonnucleon collisions [72][73][74]. Therefore, the cases defined as fusion from TDHF simulations might lead to reseparation (quasifission) if dissipation mechanisms beyond the mean-field level were included in the calculations.…”

Section: A Extra-push Energymentioning

confidence: 99%

Microscopic analysis of fusion hindrance in heavy nuclear systems

Washiyama

2015

Phys. Rev. C

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Background: Heavy-ion fusion reactions involving heavy nuclei at energies around the Coulomb barrier exhibit fusion hindrance, where the probability of compound nucleus formation is strongly hindered compared with that in light-and medium-mass systems. The origin of this fusion hindrance has not been well understood from a microscopic point of view.Purpose: Analyze the fusion dynamics in heavy systems by a microscopic reaction model and understand the origin of the fusion hindrance. Method:We employ the time-dependent Hartree-Fock (TDHF) theory as a microscopic reaction model. We extract nucleus-nucleus potential and energy dissipation by the method combining TDHF dynamics of the entrance channel of fusion reactions with one-dimensional Newton equation including a dissipation term. Then, we analyze the origin of the fusion hindrance using the properties of the extracted potential and energy dissipation.Results: We obtain finite extra-push energies for heavy systems from TDHF simulations, which agree with experimental observations. Extracted nucleus-nucleus potentials show monotonic increase as the relative distance of two nuclei decreases, which induces the disappearance of an ordinary barrier structure of the nucleus-nucleus potential. This is different from those in light-and medium-mass systems and from density-constraint TDHF calculations. Extracted friction coefficients show sizable energy dependence and universal value of their magnitude, which are rather similar to those in light-and medium-mass systems. Using these properties, we analyze the origin of the fusion hindrance and find that contribution of the increase in potential to the extra-push energy is larger than that of the accumulated dissipation energy in most systems studied in this article. Conclusions:We find that the nucleus-nucleus potentials extracted in heavy systems show a specific property, which is not observed in light-and medium-mass systems. By the analysis of the origin of the fusion hindrance, we conclude that, as the system becomes heavier, the dynamical increase in nucleus-nucleus potential at small relative distances plays a more important role than the dissipation during the fusion reaction for understanding the origin of the fusion hindrance.

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Section: A Extra-push Energymentioning

confidence: 99%

Microscopic analysis of fusion hindrance in heavy nuclear systems

Washiyama

2015

Phys. Rev. C

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“…The main shortcoming of empirical CC approaches is the choice of the distribution function of barriers which are responsible for couplings of relative motion to intrinsic degrees of freedom. In most of the empirical CC approaches, the barrier distribution has only one maximum, while the experimental barrier distributions extracted from the capture excitation functions, i. been also used to explore the fusion dynamics [50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65]. In recent years, Sargsyan et al developed a quantum diffusion approach [66][67][68] for describing the capture process, which is based on the quantum master equation for the reduced density matrix.…”

Section: Introductionmentioning

confidence: 99%

Systematics of capture and fusion dynamics in heavy-ion collisions

Wang

Wen

Zhao

et al. 2017

Atomic Data and Nuclear Data Tables

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We perform a systematic study of capture excitation functions by using an empirical coupled-channel model. In this model, a barrier distribution is used to take effectively into account the effects of couplings between the relative motion and intrinsic degrees of freedom. The shape of the barrier distribution is of an asymmetric Gaussian form. The effect of neutron transfer channels is also included in the barrier distribution. Based on the interaction potential between the projectile and the target, empirical formulas are proposed to determine the parameters of the barrier distribution.Theoretical estimates for barrier distributions and calculated capture cross sections together with experimental cross sections of 220 reaction systems with 182 Z P Z T 1640 are tabulated. The results show that our empirical formulas work quite well in the energy region around the Coulomb barrier. This model can provide prediction of capture cross sections for the synthesis of superheavy nuclei as well as valuable information on capture and fusion dynamics.

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“…Very few attempts have been made using the different Skyrme forces to study the low energy phenomena like fusion of two nuclei, their excitation functions etc. [9][10][11][12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

The systematic study of N/Z dependence on surface diffuseness parameter in the fusion of heavy neutron-rich colliding nuclei

Mittal¹,

Dutt²

2016

AIP Conference Proceedings

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Surface diffuseness parameter used in Woods-Saxon form of potential have been extracted from a large number of experimentally studied neutron-rich fusion cross sections at near barrier energies. It is clear from the literature that the exact value of diffuseness parameter suitable for fusion process is still not clear. On the other hand, various theoretical model developed so far have also employed quite arbitrary value for this parameter. We systematically analyze the collisions of 12 C +

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Energy dependence of the nucleus-nucleus potential and the friction parameter in fusion reactions

Cited by 18 publications

References 82 publications

Microscopic analysis of fusion hindrance in heavy nuclear systems

Microscopic analysis of fusion hindrance in heavy nuclear systems

Systematics of capture and fusion dynamics in heavy-ion collisions

The systematic study of N/Z dependence on surface diffuseness parameter in the fusion of heavy neutron-rich colliding nuclei

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