High-<i>K</i>isomers and rotational structures in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:mi mathvariant="normal">W</mml:mi><mml:mprescripts /><mml:none /><mml:mrow><mml:mn>174</mml:mn></mml:mrow></mml:mmultiscripts></mml:math>

Chowdhury, P.; Seabury, E. H.; Ahmad, I.; Carpenter, M. P.; Fischer, S. M.; Janssens, R. V. F.; Khoo, T. L.; Lauritsen, T.; Lister, C. J.; Seweryniak, D.; Shimizu, Yoshifumi R.

doi:10.1103/physrevc.73.044306

Cited by 29 publications

(41 citation statements)

References 32 publications

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“…Nevertheless, data covering a broader range of nuclei are needed to test the general applicability of these ideas. To date, well defined half-lives and decay properties for multiquasiparticle, high-K isomers, involving two or more broken nucleon pairs, have existed only for a small region of nuclei with 70 Z 76 and 102 * p.walker@surrey.ac.uk N 108 [7,[10][11][12][13]. The best examples outside this region are 254 102 No (which will be discussed later) where the decay properties remain to be confirmed [14,15], and the present case of a T 1/2 170 ns isomer in 164 68 Er [16].…”

Section: Introductionmentioning

confidence: 99%

Hindered decays from a non-yrast four-quasiparticle isomer in164Er

et al. 2012

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The half-life of a K π = 12 + isomer in 164 Er has been measured to be 68(2) ns, and new decay pathways have been identified. These include highly K-forbidden γ -ray transitions directly to the ground-state rotational band, with reduced hindrance values that can be compared with those found for heavier nuclides. The new data support the interpretation that the level density is a key variable in determining K-forbidden transition rates.

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Section: Introductionmentioning

confidence: 99%

Hindered decays from a non-yrast four-quasiparticle isomer in164Er

et al. 2012

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“…For both, the proton and neutron pair-gap energies were obtained from experimental masses following the procedure described in Refs. [34,35]. The results from UC and WS calculations are presented below in terms of corresponding deformation parameters ǫ 2 , ǫ 4 , and β 2 , β 4 , respectively.…”

Section: B Cranked Shell-model Calculationsmentioning

confidence: 99%

Rotation-aligned isomer and oblate collectivity inPt196

Wahid¹,

Chowdhury²,

Janssens³

et al. 2015

Phys. Rev. C

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An oblate rotational sequence, built on an aligned, two-quasineutron isomeric state has been established in 196 Pt. The isomer has a half-life of 7.7(7) ns and is associated with the I π =12 + , (i 13/2 ) 2 neutron configuration. Excited states, with angular momentum generated primarily through successive nucleon alignments, have been populated through 1p transfer from 197 Au. The nucleus 196 Pt is the most neutron-rich Pt isotope for which high-spin states, beyond the 12 + isomeric state, have been established thus far. Cranked shell model calculations have been performed to understand shape evolution with spin, and the role of nucleons occupying specific Nilsson orbitals in generating aligned angular momentum for both prolate and oblate deformations has been explored.

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“…This nucleus is also characterized by low-K and high-K bands up to highly excited states, 39h [44]. In particular, two high-K bands based on K = 8 and K = 12 isomeric states with half-lives of 158 ns and 128 ns have been observed [42]. From PSM analysis, we see that the K = 8 isomeric state has a two-qp structure with a dominant configuration of π 7/2…”

mentioning

confidence: 90%

“…The rotating nucleus 174 W exhibits axially prolate shape for a wide range of rotational frequencies [42,43]. The yrast band has been established to 38h [44].…”

mentioning

confidence: 99%

Systematic study of multi-quasiparticleK-isomeric bands in tungsten isotopes by the extended projected shell model

Ghorui

Wang

et al. 2017

Phys. Rev. C

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Background:The interplay between collective and single-particle degrees of freedom is an important structure aspect to study. The nuclei in the A ≈ 180 mass region are often denoted as good examples to study such problems because these nuclei are known to exhibit many rotational bands based on multi-quasiparticle K isomers. Purpose: A large set of high-quality experimental data on high-K isomeric states in the A ≈ 180 mass region has accumulated. A systematic description of them is a theoretical challenge as it requires a method going beyond the usual mean field with multi-quasiparticle configurations built in the shell-model basis. The K-isomer data provide an ideal testing ground for theoretical models. Method:The recently extended projected shell model (PSM) by the Pfaffian method is employed with a sufficiently large configuration space including up to 10 quasiparticles. The restoration of rotational symmetry which is broken in the deformed mean field is obtained by means of angular-momentum projection. With axial symmetry in the basis deformation, each multi-quasiparticle state, classified by a K quantum number, represents the major component of a rotational K band. Shell-model diagonalization in such a projected basis defines the K mixing, which is the key ingredient of the present method. Results: Quasiparticle structure and rotational properties of high-K isomers in even-even neutron-rich 174−186 W isotopes are described. The rotational evolution of the yrast and near-yrast bands is discussed with successive band crossings. Multi-quasiparticle K isomers and associated rotational bands in each W isotope are studied with detailed quasiparticle configurations given. Electromagnetic transition properties are also studied and the calculated B(E2), B(M1), and g-factors are compared with experiment if data exist. Conclusions: Many nuclei of the A ≈ 180 mass region exhibit properties of an axially symmetric shape and K is approximately a good quantum number. For such nuclei, the extended PSM assuming an axially symmetric basis but including K mixing through diagonalization of the two-body Hamiltonian is an appropriate method to study multi-quasiparticle K isomers and K violations in these states. For special examples where one finds highly K-forbidden transitions the present model needs to be further improved.

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High-Kisomers and rotational structures inW174

Cited by 29 publications

References 32 publications

Hindered decays from a non-yrast four-quasiparticle isomer in164Er

Hindered decays from a non-yrast four-quasiparticle isomer in164Er

Rotation-aligned isomer and oblate collectivity inPt196

Systematic study of multi-quasiparticleK-isomeric bands in tungsten isotopes by the extended projected shell model

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