Shape coexistence and shape transition in nuclei from krypton to molybdenum

Petrovici, A.; Schmid, K.W.; Faessler, Amand

doi:10.1016/0375-9474(96)00224-2

Cited by 68 publications

(85 citation statements)

References 26 publications

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“…These gross features are consistent with available experimental data [60][61][62][63][64][65][66] and previous theoretical calculations [19,21,22,49,[67][68][69][70][71][72][73][74][75][76][77].…”

Section: Quadrupole Deformationssupporting

confidence: 92%

Symmetry-unrestricted Skyrme–Hartree–Fock–Bogoliubov calculations for exotic shapes in nuclei from 64Ge to 84Mo

2001

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By performing fully 3D symmetry-unrestricted Skyrme-Hartree-FockBogoliubov calculations, we discuss shape coexistence and possibility of exotic deformations simultaneously breaking the reflection and axial symmetries in proton-rich N = Z nuclei: 64 Ge, 68 Se, 72 Kr, 76 Sr, 80 Zr and 84 Mo. Results of calculation indicate that the oblate ground state of 68 Se is extremely soft against the Y 33 triangular deformation, and that the low-lying spherical minimum coexisting with the prolate ground state in 80 Zr is extremely soft against the Y 32 tetrahedral deformation.

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Section: Quadrupole Deformationssupporting

confidence: 92%

Symmetry-unrestricted Skyrme–Hartree–Fock–Bogoliubov calculations for exotic shapes in nuclei from 64Ge to 84Mo

2001

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“…When we compare our experimental results with the theoretical calculations of Ref. [12] we conclude that the ground state of 76 Sr is strongly prolate (β 2 ≈0.4), in agreement with theoretical predictions [4,7] and with previous experimental indications [10,14,15]. An important consequence of the present work is the validation of the method of deducing the deformation, including the sign of the quadrupole moment, from the comparison of the β-decay TAgS results and the calculated B(GT) since the 76 Sr ground state is a very clean case, free of shape admixtures.…”

supporting

confidence: 88%

“…As a result Mean Field calculations predict the existence of several energy minima with quite different shapes in some of these nuclei [3,4]. Evidence of this co-existence has been found for instance in Se and Kr nuclei [5,6], and it is also predicted for the lightest Sr isotopes [7]. Thus it is of considerable interest to map out the deformation of the ground and excited states of nuclei in this region.…”

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confidence: 90%

Deformation of theN=ZNucleusSr76usingβ-Decay Studies

et al. 2004

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A novel method of deducing the deformation of the N=Z nucleus 76 Sr is presented. It is based on the comparison of the experimental Gamow-Teller strength distribution B(GT) from its β-decay with the results of QRPA calculations. This method confirms previous indications of the strong prolate deformation of this nucleus in a totally independent way. The measurement has been carried out with a large Total Absorption gamma Spectrometer, "Lucrecia", newly installed at CERN-ISOLDE.PACS numbers: 21.10. Pc, 23.40.Hc, 27.50.+e, 29.30.Kv, 29.40.Mc The shape of the atomic nucleus is conceptually one of the simplest of its macroscopic properties to visualise. However, it turns out to be one of the more difficult properties to measure. In general terms we now have a picture of how the nuclear shape varies across the Segrè Chart. Nuclei near to the closed shells are spherical. In contrast nuclei with the valence nucleons in between two shells have deformed shapes with axial symmetry and the extent of the quadrupole deformation is quite well described as being proportional to the product N p N n of the numbers of pairs of valence protons (N p ) and neutrons (N n ) [1]. This picture is underpinned by both the Shell and Mean Field models of nuclear structure. Experiment and theory concur that, as the N p N n parameterisation would suggest, nuclei rapidly deform as we add only a small number of valence nucleons to the magic numbers. Thus nuclei in the middle of the f 7/2 shell turn out to be deformed even although the numbers of valence nucleons are relatively small.Experimentally this picture is supported by a mass of independent observations: the strongly enhanced quadrupole transition rates between low-lying states, the strongly developed rotational bands built on low-lying states, and measurements of ground state quadrupole moments. Where we have evidence of the shapes of ground and excited states in the same nucleus they are, in general but not always, the same. It turns out that in some cases nuclear states with different shapes co-exist in the same nucleus [2].The nuclei with N≈Z and A≈70-80 are of particular interest in this context. Such nuclei enjoy a particular symmetry since the neutrons and protons are filling the same orbits. This, and the low single-particle level density, lead to rapid changes in deformation with the addition or subtraction of only a few nucleons. In terms of Mean Field models these rapid changes arise because of the proximity in energy of large energy gaps for protons and neutrons at Z,N=34 and 36 on the oblate and Z,N=38 on the prolate side of the Nilsson diagram. As a result Mean Field calculations predict the existence of several energy minima with quite different shapes in some of these nuclei [3,4]. Evidence of this co-existence has been found for instance in Se and Kr nuclei [5,6], and it is also predicted for the lightest Sr isotopes [7]. Thus it is of considerable interest to map out the deformation of the ground and excited states of nuclei in this region. This is easier said than do...

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“…The present results can then be used as a guidance to further experimental searches. It is also worth mentioning that this mass region is known to present particular structure effects, such as shape coexistence, which are the result of a delicate balance of competing nuclear shapes [7,15]. It is then important to explore whether the dependence of the beta-decay properties on the deformation of the parent nucleus could be used as an additional piece of information to elucidate the shape of the nucleus.…”

Section: Introductionmentioning

confidence: 99%

Spin–isospin excitations and half-lives of medium-mass deformed nuclei

2001

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A selfconsistent approach based on a deformed HF+BCS+QRPA method with density-dependent Skyrme forces is used to describe β + -decay properties in even-even deformed proton rich nuclei. Residual spin-isospin forces are included in the particle-hole and particle-particle channels. The quasiparticle basis contains neutron-neutron and proton-proton pairing correlations in the BCS approach, while neutron-proton pairing interaction is treated as a residual force in QRPA. We discuss the sensitivity of Gamow-Teller strength distributions and β + /EC half-lives to deformation, pairing and the strength of the particle-particle interaction. The dependence on deformation is also compared to that of spin M 1 strength distributions.

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Shape coexistence and shape transition in nuclei from krypton to molybdenum

Cited by 68 publications

References 26 publications

Symmetry-unrestricted Skyrme–Hartree–Fock–Bogoliubov calculations for exotic shapes in nuclei from 64Ge to 84Mo

Symmetry-unrestricted Skyrme–Hartree–Fock–Bogoliubov calculations for exotic shapes in nuclei from 64Ge to 84Mo

Deformation of theN=ZNucleusSr76usingβ-Decay Studies

Spin–isospin excitations and half-lives of medium-mass deformed nuclei

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