Spectroscopy of neutron-rich Te and Xe isotopes within a new shell model context

Bianco, Davide; Iudice, N. Lo; Andreozzi, F.; Porrino, A.; Knapp, F.

doi:10.1103/physrevc.88.024303

Cited by 34 publications

(32 citation statements)

References 68 publications

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“…This is quite a striking result that is not expected by the present theoretical, or empirical predictions, for instance, see Ref. [24] in which 140 Te was described like a triaxial rotator with R = 2.33. The characteristics in the R systematics are as follows: for Te there is little difference in the R values, giving R ~ 0; for Sn, the differences are constant at R ~ -0.175; for Xe and Ba, the values split into three regimes; positive, close to zero, and negative; for Ce ( Z = 58) to Dy ( Z = 66) the lines have two branches which extend into the negative region, and, finally, for N = 88 there is a distinctive peak at Z = 56 and a pronounced valley at Z = 64.…”

supporting

confidence: 45%

“…The discrepancy was explained by the quasiparticle random phase approximation as a neutron-pairing reduction [22] and by the Monte Carlo Shell Model as neutron dominance through asymmetric proton-neutron couplings [23]. Furthermore, a large scale shell model calculation also pointed out the importance of the neutron dominance in the wave function of excited states in neutronrich Te isotopes [24]. A recent study [8] showed that the ratio of the first 4 + to 2 + energies, E(4 + )/E(2 + ) for 138 Te, with N = 86, is identical to that of 130 Te with N = 78.…”

mentioning

confidence: 99%

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Nuclear structure and β -decay schemes for Te nuclides beyond N=82

Moon¹,

Moon²,

Söderström³

et al. 2017

Phys. Rev. C

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We study for the first time the internal structure of Te produced by the -decay branch, the -delayed one-neutron and two-neutron emission branches were also established. By identifying the first 2 + and 4 + excited states of 140 Te, we found that Te isotopes persist their vibrator character with E(4 + )/E(2 + ) = 2. We discuss the distinctive features manifest in this region, such as valence neutron symmetry and asymmetry, revealed in pairs of isotopes with the same neutron holes and particles with respect to N = 82.

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supporting

confidence: 45%

mentioning

confidence: 99%

Nuclear structure and β -decay schemes for Te nuclides beyond N=82

Moon¹,

Moon²,

Söderström³

et al. 2017

Phys. Rev. C

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“…Large-scale shell model (LSSM) calculations were performed by Bianco et al [26]. The shell-model space used for the calculation included the 1g 7/2 ,2d 5/2 , 2d 3/2 , 3s 1/2 , 1h 11/2 orbitals for protons and 2f 7/2 , 3p 3/2 , 1h 9/2 , 3p 1/2 , 2f 5/2 , 1i 13/2 for neutrons.…”

Section: Comparison With Theorymentioning

confidence: 99%

Measurement of picosecond lifetimes in neutron-rich Xe isotopes

Ilieva

Kroll²,

Régis³

et al. 2016

Phys. Rev. C

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Background: Lifetimes of nuclear excited states in fission fragments have been studied in the past following isotope separation, thus giving access mainly to the fragments' daughters and only to long-lived isomeric states in the primary fragments. For the first time now, short-lived excited states in the primary fragments, produced in neutron-induced prompt fission of 235 U and 241 Pu, were studied within the EXILL&FATIMA campaign at the intense neutron-beam facility of the Institute Laue-Langevin in Grenoble. Purpose: We aim to investigate the quadrupole collective properties of neutron-rich even-even 138,140,142 Xe isotopes lying between the double shell closure N = 82 and Z = 50 and a deformed region with octupole collectivity. Method: The γ rays emitted from the excited fragments were detected with a mixed array consisting of 8 HPGe EXOGAM Clover detectors (EXILL) and 16 LaBr 3 (Ce) fast scintillators (FATIMA). The detector system has the unique ability to select the interesting fragment making use of the high resolution of the HPGe detectors and determine subnanosecond lifetimes using the fast scintillators. For the analysis the generalized centroid difference method was used. Results: We show that quadrupole collectivity increases smoothly with increasing neutron number above the closed N = 82 neutron shell. Our measurements are complemented by state-of-the-art theory calculations based on shell-model descriptions. Conclusions:The observed smooth increase in quadrupole collectivity is similar to the evolution seen in the measured masses of the xenon isotopic chain and is well reproduced by theory. This behavior is in contrast to higher Z even-even nuclei where abrupt change in deformation occurs around N = 90.

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“…The excitation energies, transition rates, and static moments are sensitive to shell structure, the strength of the proton-neutron interactions, and to developing collectivity [1][2][3][4][5][6][7][8][9][10]. Following the observation of an anomalously low B(E2; 0 + 1 → 2 + 1 ) by Radford et al [11], the case of 136 Te, with two protons and two neutrons outside the 132 Sn core, has been the subject of many theoretical studies, with widely varying predictions of the electromagnetic properties of the low-excitation states [1-5, 9, 10].…”

Section: Introductionmentioning

confidence: 99%

First-excited state g factor of Te136 by the recoil in vacuum method

et al. 2017

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The g factor of the first 2 + state of radioactive 136 Te with two valence protons and two valence neutrons beyond double-magic 132 Sn has been measured by the Recoil in Vacuum (RIV) method. The lifetime of this state is an order of magnitude longer than the lifetimes of excited states recently measured by the RIV method in Sn and Te isotopes, requiring a new evaluation of the free-ion hyperfine interactions and methodology used to determine the g factor. The calibration data are reported and the analysis procedures are described in detail. The resultant g factor has a similar magnitude to the g factors of other nuclei with an equal number of valence protons and neutrons in the major shell. However, an unexpected trend is found in the g factors of the N = 84 isotones, which decrease from 136 Te to 144 Nd. Shell model calculations with interactions derived from the CD Bonn potential show good agreement with the g factors and E2 transition rates of 2 + states around 132 Sn, confirming earlier indications that 132 Sn is a good doubly magic core.

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Spectroscopy of neutron-rich Te and Xe isotopes within a new shell model context

Cited by 34 publications

References 68 publications

Nuclear structure and β -decay schemes for Te nuclides beyond N=82

Nuclear structure and β -decay schemes for Te nuclides beyond N=82

Measurement of picosecond lifetimes in neutron-rich Xe isotopes

First-excited state g factor of Te136 by the recoil in vacuum method

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