Spontaneous fission with<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>β</mml:mi></mml:math>-parameterized quasimolecular shape

Zhang, Haifei; Zhang, Hongfei; Li, Junqing; Bao, Xiao Jun; Ma, Nana

doi:10.1103/physrevc.90.054313

Cited by 11 publications

(10 citation statements)

References 29 publications

(43 reference statements)

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“…Unlike other models, the Generalized Liquid Drop Model (GLDM) has two major advantages: introducing the quasimolecular shape mechanism [37], which can describe the complex deformation process from the parent nucleus continuous transition to the appearance of a deep and narrow neck, finally resulting in two tangential fragments, and adding the proximity energy, including an accurate radius and mass asymmetry. When a neck or a gap appears in one-body shapes or between separated fragments, proximity energy plays a key role in taking into account the effects of the nuclear forces between the close surfaces, balancing the repulsion of the Coulomb barrier, and reasonably constructing the barrier heights and positions of the nucleus in complex deformation processes [37][38][39][40]. Therefore, the GLDM can successfully deal with proton radioactivity [41], cluster radioactivity [42], fusion [43], fission [44] and the α decay process [22,37,40,[45][46][47][48].…”

Section: Introductionmentioning

confidence: 99%

Systematic study of α decay half-lives within the Generalized Liquid Drop Model with various versions of proximity energies *

Deng¹,

Zhang²

2021

Chinese Phys. C

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It is universally acknowledged that the Generalized Liquid Drop Model (GLDM) has two advantages over other α decay theoretical models: introduction of the quasimolecular shape mechanism and proximity energy. In the past few decades, the original proximity energy has been improved by numerous works. In the present work, the different improvements of proximity energy are examined when they are applied to the GLDM for enhancing the calculation accuracy and prediction ability of α decay half-lives for known and unsynthesized superheavy nuclei. The calculations of α half-lives have systematic improvements in reproducing experimental data after choosing a more suitable proximity energy for application to the GLDM. Encouraged by this, the α decay half-lives of even-even superheavy nuclei with Z=112-122 are predicted by the GLDM with a more suitable proximity energy. The predictions are consistent with calculations by the improved Royer formula and the universal decay law. In addition, the features of the predicted α decay half-lives imply that the next double magic nucleus after 208Pb is 298Fl.

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Section: Introductionmentioning

confidence: 99%

Systematic study of α decay half-lives within the Generalized Liquid Drop Model with various versions of proximity energies *

Deng¹,

Zhang²

2021

Chinese Phys. C

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“…We refer the reader, for instance, to Refs. [1][2][3][4] and references therein. Macroscopic-microscopic model calculations predicted, already in the 1970s [5][6][7], the occurrence of shallow third minima beyond the second barrier.…”

Section: Introductionmentioning

confidence: 99%

Multidimensionally constrained relativistic mean-field study of triple-humped barriers in actinides

et al. 2015

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Background: Potential energy surfaces (PES's) of actinide nuclei are characterized by a two-humped barrier structure. At large deformations beyond the second barrier, the occurrence of a third barrier was predicted by macroscopic-microscopic model calculations in the 1970s, but contradictory results were later reported by a number of studies that used different methods. Purpose: Triple-humped barriers in actinide nuclei are investigated in the framework of covariant density functional theory (CDFT). Methods: Calculations are performed using the multidimensionally constrained relativistic mean field (MDC-RMF) model, with the nonlinear point-coupling functional PC-PK1 and the density-dependent meson exchange functional DD-ME2 in the particle-hole channel. Pairing correlations are treated in the BCS approximation with a separable pairing force of finite range. Results: Two-dimensional PES's of 226.228.230,232 ancj 2 3 2 .2 3 4 .2 3 6 .2 3 8 y are mappe(i and the third minima on these surfaces are located. Then one-dimensional potential energy curves along the fission path are analyzed in detail and the energies of the second barrier, the third minimum, and the third barrier are determined. The functional DD-ME2 predicts the occurrence of a third barrier in all Th nuclei and 238U. The third minima in 230.2327}, are very shallow, whereas those in 226.2287}, and 238U are quite prominent. With the functional PC-PK1 a third barrier is found only in 226 .2 2 8 .2 3 0 7 }, single-nucleon levels around the Fermi surface are analyzed in 226Th, and it is found that the formation of the third minimum is mainly due to the Z = 90 proton energy gap at f 2o ~ 1 -5 and fto » 0.7. Conclusions: The possible occurrence of a third barrier on the PES's of actinide nuclei depends on the effective interaction used in multidimensional CDFT calculations. More pronounced minima are predicted by the DD-ME2 functional, as compared to the functional PC-PK1. The depth of the third well in Th isotopes decreases with increasing neutron number. The origin of the third minimum is due to the proton Z = 90 shell gap at relevant deformations.

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“…β 20 ), or by minimizing the fission action integral in the collective space. Static fission paths obtained by minimizing the collective energy computed with the macroscopicmicroscopic (MM) model [13][14][15] and various self-consistent mean-field (SCMF) models [16][17][18][19][20][21][22][23][24] have been used to calculate SF half-lives.…”

Section: Introductionmentioning

confidence: 99%

Multidimensionally constrained relativistic Hartree-Bogoliubov study of spontaneous nuclear fission

et al. 2015

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Background: Recent microscopic studies, based on the theoretical framework of nuclear energy density functionals, have analyzed dynamic (least action) and static (minimum energy) fission paths, and it has been shown that in addition to the important role played by nonaxial and/or octupole collective degrees of freedom, fission paths crucially depend on the approximations adopted in calculating the collective inertia.Purpose: To analyse effects of triaxial and octupole deformations, as well as approximations to the collective inertia, on the symmetric and asymmetric spontaneous fission dynamics, and compare with results of recent studies based on the self-consistent Hartree-Fock-Bogoliubov (HFB) method.Methods: Deformation energy surfaces, collective potentials, and perturbative and nonperturbative cranking collective inertia tensors are calculated using the multidimensionally-constrained relativistic Hartree-Bogoliubov (MDC-RHB) model, with the energy density functionals PC-PK1 and DD-PC1. Pairing correlations are treated in the Bogoliubov approximation using a separable pairing force of finite range. The least-action principle is employed to determine dynamic spontaneous fission paths. Results: The dynamics of spontaneous fission of 264 Fm and 250 Fm is explored. The fission paths, action integrals and the corresponding half-lives predicted by the functionals PC-PK1 and DD-PC1 are compared and, in the case of 264 Fm, discussed in relation with recent results obtained using the HFB model based on the Skyrme functional SkM * and a density dependent mixed pairing interaction.Conclusions: The inclusion of nonaxial quadrupole and octupole shape degrees of freedom is essential for a quantitative analysis of fission dynamics. The action integrals and, consequently, the half-lives crucially depend on the approximation used to calculate the effective collective inertia along the fission path. The perturbative cranking approach underestimates the effects of structural changes at the level crossings and the resulting collective inertia varies relatively smoothly in the (β 20 , β 22 ) and (β 20 , β 30 ) planes. In contrast, the nonperturbative collective mass is characterized by the occurrence of sharp peaks on the surface of collective coordinates, that can be related to single-particle level crossings near the Fermi surface. This enhances the effective inertia, increases the values of the action integral, and results in longer fission half-lives.

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Spontaneous fission withβ-parameterized quasimolecular shape

Cited by 11 publications

References 29 publications

Systematic study of α decay half-lives within the Generalized Liquid Drop Model with various versions of proximity energies *

Systematic study of α decay half-lives within the Generalized Liquid Drop Model with various versions of proximity energies *

Multidimensionally constrained relativistic mean-field study of triple-humped barriers in actinides

Multidimensionally constrained relativistic Hartree-Bogoliubov study of spontaneous nuclear fission

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