Two-quasiparticle and rotation-aligned structures in 190Pt, 192Pt and 194Pt

Hjorth, S.A.; Johnson, A.; Lindblad, Th.; Funke, L.; Kemnitz, P.; Winter, G.

doi:10.1016/0375-9474(76)90625-4

Cited by 86 publications

(64 citation statements)

References 30 publications

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“…In the top panel of A backbending at similar frequencies and with similar alignment gain is observed throughout this region, e.g. for the neighboring doubly-odd 190−194 Hg [33] and 186−190 Au [17,34] and even-even 190,192 Pt [32,35,36]. In Fig.…”

Section: A Negative Parity Statessupporting

confidence: 54%

Triaxial deformation and nuclear shape transition in192Au

Öktem¹,

Balabanski

Akkuš³

et al. 2012

Phys. Rev. C

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Background : Nuclei in A ≈ 190 mass region show gradual shape changes from prolate through non-axial deformed shapes and ultimately towards spherical shapes as the Pb region is approached. Exploring how this shape evolution occurs will help understand the evolution of collectivity in this region. Purpose : The level scheme of the 192 Au nucleus in A ≈ 190 region was studied in order to deduce its deformations. Methods : High-spin states of 192 Au have been populated in the 186 W( 11 B, 5n) reaction at a beam energy of 68 MeV and their γ decay was studied using the YRAST Ball detector array at the WNSL, Yale University. Results : Based on double and triple γ-ray coincidence data the level scheme of 192 Au has been extended up to I π = 32 + at an excitation energy of ∼ 6 MeV. Conclusion : The results are discussed in the framework of pairing and deformation self-consistent Total Routhian Surface (TRS) and Cranked Shell Model (CSM) calculations. The comparison of the experimental observations with the calculations indicates that this nucleus takes non-axial shape similar to other Au nuclei in this region.

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Section: A Negative Parity Statessupporting

confidence: 54%

Triaxial deformation and nuclear shape transition in192Au

Öktem¹,

Balabanski

Akkuš³

et al. 2012

Phys. Rev. C

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“…Gamma softness in varying degrees is a feature common to all Pt isotopes owing to the relatively small number of valence nucleons. For the doubly-even Pt isotopes, a rather sudden change in the energy sequence of the yrast, positive-parity, structure is evident around 10-12 in 188−194 Pt [2,5]. In fact, the 12 + state is isomeric, and the rotational sequence built on this level is characterized by a moment of inertia much larger than that of the ground-state band.…”

Section: Introductionmentioning

confidence: 93%

“…While collectivity diminishes with increasing neutron number, oblate rotation-aligned states tend to be favored at high spin over prolate excitations, in isotopes of Hf (Z=72) to Hg (Z=80) [1][2][3][4]. Substantial high-spin information is available for lighter Pt isotopes [2,5] which are accessible through heavy-ion fusion evaporation reactions. Isotopes of Pt (Z=78), beginning with 196 Pt, can be reached only through either inelastic excitation, multi-nucleon transfer or projectile fragmentation reactions [6,7].…”

Section: Introductionmentioning

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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“…Since low-Ω orbitals typically exhibit a higher degree of alignment compared to high-Ω ones over a similar range of rotational frequency, oblate states are found to be lower in energy than the corresponding prolate ones. While this phenomenon was first predicted quite some time ago [2], as yet, there are a relatively small number of nuclei where collective oblate rotation is experimentally observed to the favored excitation mode [3][4][5]. Oblate shapes are expected to be more favored in neutron-rich nuclei however these are experimentally difficult to explore.…”

Section: Introductionmentioning

confidence: 95%

“…Proton-rich Pt isotopes have been studied rather extensively e.g. [4,8,9], a e-mail: sujit.tandel@cbs.ac.in and found to exhibit well-developed rotational bands both near the ground states and at high spin. With increase in neutron number from the lightest stable isotope 190 Pt (N=112) to the heaviest 198 Pt (N = 120), the decrease in ground state deformation and collectivity is evidenced by the increase in 2 + 1 excitation energy in even-A nuclei accompanied by a corresponding reduction in B(E2; 2 + →0 + ) values.…”

Section: Introductionmentioning

confidence: 99%

Isomers and oblate collectivity at high spin in neutron-rich Pt isotopes

Tandel

2016

EPJ Web of Conferences

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Abstract. Isomers and high-spin structures with rotation-aligned oblate configurations have been studied in several Pt isotopes. The 12 + states in the even Pt isotopes from 192−198 Pt are found to be metastable, and have (i 13/2 ) 2 neutron character. The progression of E2 transition probabilities from the 12 + to 10 + states across the Pt isotopic chain implies reduction in collectivity, followed by an abrupt decrease at N=120 ( 198 Pt). This behavior is quite distinct from the gradual decrease of B(E2) values near the respective ground states. A large contribution from aligned angular momentum, to the rotational sequences built on the 12 + states, is visible. This is due to the relatively small crossing frequencies for nucleons in low-Ω orbitals at oblate deformation in comparison to higher values for prolate shapes. As a result, oblate rotation is found to be increasingly favored for higher neutron numbers.

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Two-quasiparticle and rotation-aligned structures in 190Pt, 192Pt and 194Pt

Cited by 86 publications

References 30 publications

Triaxial deformation and nuclear shape transition in192Au

Triaxial deformation and nuclear shape transition in192Au

Rotation-aligned isomer and oblate collectivity inPt196

Isomers and oblate collectivity at high spin in neutron-rich Pt isotopes

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