Properties of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msubsup><mml:mn>0</mml:mn><mml:mrow><mml:mn>2</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msubsup></mml:mrow></mml:math>state and isospin excitation in the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>N</mml:mi><mml:mo>=</mml:mo><mml:mi>Z</mml:mi></mml:mrow></mml:math>nucleus<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" displa

Al-Khudair, Falih H.; Li, Y. S.; Long, Gui Lu

doi:10.1103/physrevc.75.054316

Cited by 23 publications

(14 citation statements)

References 54 publications

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“…The case of the selenium isotopes is less clear. Low-lying excited 0 + states, characteristic of shape coexistence, are predicted at about 1 MeV in light selenium isotopes [6,7,8,9] but have not been observed so far in T z = 0 and T z = 1 isotopes, in contrast to the krypton case. Shape coexistence is found in 72 Se with a low-lying 0 + state at 937 keV and a strong mixing of intrinsic configurations at low spin [10].…”

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confidence: 82%

First spectroscopy of 66Se and 65As: Investigating shape coexistence beyond the N=Z line

et al. 2011

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We report on the first γ spectroscopy of 66 Se and 65 As from two-neutron removal at intermediate beam energies. The deduced excitation energies for the first-excited states in 66 Se and 65 As are compared to mean-field-based predictions within a collective Hamiltonian formalism using the Gogny D1S effective interaction and to state-of-the-art shell-model calculations restricted to the pf 5/2 g 9/2 valence space. The obtained Coulomb-energy differences for the first excited states in 66 Se and 65 As are discussed within the shell-model formalism to assess the shape-coexistence picture for both nuclei. Our results support a favored oblate ground-state deformation in 66 Se and 65 As. A shape transition for the ground state of even-odd As isotopes from oblate in 65 As to prolate in 67,69,71 As is suggested.

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confidence: 82%

First spectroscopy of 66Se and 65As: Investigating shape coexistence beyond the N=Z line

et al. 2011

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“…In this work, we considered the five quadrupole collective degrees of freedom. This formalism has already been shown to reproduce the shape transition The measured value in this work for 68 Se is compared to predictions from different theories: our beyond-mean-field calculations indicated by open triangles; adiabatic self-consistent collective coordinate [9]; excited VAMPIR [10]; SM-pfgd [11]; IBM-3 [12]. (Bottom) Experimental and theoretical excitation energy of the 2 + 1 states.…”

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confidence: 97%

“…However, triaxiality has been suggested to be a key degree of freedom to understand the shape transition in light krypton isotopes [8]. The importance of triaxiality in 68 Se, between the triaxial 64 Ge and the oblate 72 Kr, and its ground-state shape remain open questions.Several theories have been employed to study the deformation of 68 Se at low excitation energy and their predictions for B(E2↑)'s change from ∼0.2 to ∼2.5 times the experimental value for 64 Ge, leading to contrasted interpretations of the collectivity in 68 Se [9][10][11][12]. It is therefore of importance to measure this quantity for 68 Se to map out the shape evolution along the N = Z line.…”

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confidence: 99%

“…Several theories have been employed to study the deformation of 68 Se at low excitation energy and their predictions for B(E2↑)'s change from ∼0.2 to ∼2.5 times the experimental value for 64 Ge, leading to contrasted interpretations of the collectivity in 68 Se [9][10][11][12]. It is therefore of importance to measure this quantity for 68 Se to map out the shape evolution along the N = Z line.…”

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confidence: 99%

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Shape evolution in self-conjugate nuclei, and the transitional nucleusSe68

et al. 2009

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We report on the first measurement of the absolute transition strength B(E2; 0 + 1 → 2 + 1 ) in the self-conjugate nucleus 68 Se. It is found that the 0 + 1 → 2 + 1 transition displays a strength similar to that for the triaxial 64 Ge nucleus, in sharp contrast to the much stronger collectivity observed for the oblate 72 Kr nucleus. Shape evolution along the N = Z line from zinc to strontium is analyzed through beyond-mean-field calculations using the D1S force. Over this narrow mass region the nuclear structure shows clear-cut transition from prolate to oblate and back to prolate, with 68 Se standing as pivotal between triaxial and oblate deformations.Finite quantum systems may exhibit sudden shape transitions by changing their number of constituants, as observed in semiconductor atomic clusters [1]. In atomic nuclei, the ground state generally has a nonspherical symmetry and the deformation evolves with the number of nucleons due to both single-particle properties and quantum mechanical correlations. Steep shape transitions are expected in regions where several energy minima located at different deformations compete to stabilize the nucleus. This competition is enhanced in self-conjugate nuclei with ∼70 nucleons, in which neutrons and protons experience the same large deformed singleparticle shell gaps at both elongated (prolate) and flattened (oblate) quadrupole deformation. The sign of the spectroscopic quadrupole moment of the first 2 + state is hardly reachable in these neutron-deficient nuclei. It is experimentally known only in very few cases, such as 74,76 36 Kr [2] and 70 34 Se [3]. The B(E2; 0 + 1 → 2 + 1 ) transition strength from the ground state (gs) to the first 2 + excited state, quoted B(E2↑) in the following, thus remains a unique and reachable information to evaluate collectivity at low excitation energy. The low-lying spectroscopy of the N = Z nucleus 64 32 Ge, four nucleons away from 68 Se, shows strong similarities with predictions for a triaxial nucleus. Recently, its B(E2↑) transition strength has been measured and was found consistent with shell-model predictions for a triaxial shape [4]. In the case of the selenium isotopes, it has been concluded from recent low-energy Coulomb-excitation and 2 + 1 -lifetime measurements, that 70 Se is oblate in its gs [3]. The moment of inertia extracted from the ground-state band of 68 Se is similar to that of 70 Se and suggests a collective oblate deformation [5], but no direct information on the collectivity of 68 Se has been measured yet. In the krypton isotopes, a shape transition from a prolate-deformed gs in 76 Kr to an oblate shape in 72 Kr has been established [2,6]. The N = Z nucleus 72 Kr is understood as having an almost pure oblate ground state with very low mixing with the intrinsic prolate configuration. The absolute transition strength B(E2↑) of 72 Kr shows consistency with predictions of an oblate ground state [7]. However, triaxiality has been suggested to be a key degree of freedom to understand the shape transition in light krypton is...

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“…For lighter nuclei, the IBM has been extended to the interacting boson model with isospin (IBM-3) [12]. Within the IBM-3, the neutron-proton pair must be included in addition to the two other types of bosons in the IBM-2, and they form an isospin triplet [13,14,15,16,17]. In the interacting boson fermion model (IBFM) [18], odd-A nuclei are described by coupling the degrees of freedom of odd particle to a core which is described in the IBM.…”

Section: Introductionmentioning

confidence: 99%

Negative-parity states and β decays in odd Ho and Dy nuclei withA=151,153

2008

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We have investigated the negative-parity states and electromagnetic transitions in 151,153 Ho and 151,153 Dy within the framework of the interacting boson fermion model 2 (IBFM-2). Spin assignments for some states with uncertain spin are made based on this calculation. Calculated excitation energies, electromagnetic transitions and branching ratios are compared with available experimental data and a good agreement is obtained. The model wave functions have been used to study β-decays from Ho to Dy isotones, and the calculated log f t values are close to the experimental data.

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Properties of the02+state and isospin excitation in theN=Znucleus

Cited by 23 publications

References 54 publications

First spectroscopy of 66Se and 65As: Investigating shape coexistence beyond the N=Z line

First spectroscopy of 66Se and 65As: Investigating shape coexistence beyond the N=Z line

Shape evolution in self-conjugate nuclei, and the transitional nucleusSe68

Negative-parity states and β decays in odd Ho and Dy nuclei withA=151,153

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