Identification of 183Hg. Identical bands in 183,185Hg

doi:10.1016/0370-2693(93)91781-H

Physics Letters B

Volume 318, Issue 1, 25 November 1993, Pages 41-46

https://doi.org/10.1016/0370-2693(93)91781-H Get rights and content

Abstract

In-beam γ-ray transitions in ¹⁸³Hg have been identified from fragment-γ and γ-γ coincidence measurements using the Argonne Fragment Mass Analyzer (FMA). The γ-ray transitions in ¹⁸³Hg were placed into five bands. Two of these have been associated with the $[624] 92^{+}$ orbital and exhibit signature splitting, as expected for i $_{132}$ excitations built on a prolate shape moderate deformation. Two other bands which do not show signature splitting have been associated with the $[514] 72^{−}$ orbital and exhibit transition energies “identical” to the bands with the same configuration in ¹⁸⁵Hg.

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Cited by (13)

Odd-even shape staggering and kink structure of charge radii of Hg isotopes by the deformed relativistic Hartree–Bogoliubov theory in continuum
2023, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
We examined the shape staggering of relative charge radii in ^180−186Hg isotopes, which was first measured in 1977 and recently confirmed using advanced spectroscopy techniques. To understand the nuclear structure underlying this phenomenon, we employed the deformed relativistic Hartree–Bogoliubov theory in continuum (DRHBc). Our analysis revealed that the shape staggering can be attributed to nuclear shape transition in the Hg isotopes. Specifically, we demonstrated that prolate shapes of ^181,183,185Hg lead to an increase in the charge radii compared to oblate shapes of ^{180,182,184,186}Hg isotopes. We explained the nuclear shape staggering in terms of the evolution of occupation probability (OP) of $ν 1 i_{13 / 2}$ , $ν 1 h_{9 / 2}$ , $π 1 h_{9 / 2}$ , and $π 3 s_{1 / 2}$ states. Additionally, we clarified the kink structure of the charge radii in the Hg isotopes near $N = 126$ magic shell does not come from the change of the OP of $π 1 h_{9 / 2}$ state, but mainly by the increase of the OPs of $ν 1 i_{11 / 2}$ and $ν 2 g_{9 / 2}$ states.
First observation of the decay of the 13/2+ isomer in 183Hg and B(M2) systematics of neutron transitions across the nuclear chart
2022, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Citation Excerpt :
To reduce possible degradation of the target due to beam heating, four target sectors were mounted on a rotating wheel, and a magnetic steerer was used to wobble the beam ±2.5 mm horizontally across the target [15]. In 183Hg, several prolate-deformed rotational bands have been established experimentally [19–21], e.g., the 1/2−[521] g.s. band and a “floating” 7/2−[514] band, which are also known in the neighboring deformed nuclides, e.g., 181,185Hg and 181,183Pt [27]. Selected low-lying levels from these bands, of possible relevance to the decay of the 13/2+ isomer, are shown in Fig. 2.
The decay of the 13/2⁺ isomeric state in ¹⁸³Hg was observed for the first time following the α decay of the 13/2⁺ isomer in ¹⁸⁷Pb produced in the ¹⁴²Nd(⁵⁰Cr, 2p3n) reaction. Using $α - γ$ delayed coincidence measurements, the half-life of this isomer was measured to be 290(30) μs. This isomer is proposed to deexcite by an unobserved low-energy M2 transition to the known 9/2⁻ member of a strongly prolate-deformed 7/2⁻[514] band, followed by a 105-keV M1 transition to the bandhead. A lower limit of B(M2) ≥ 0.018 W.u. was deduced for the unobserved transition. The presumed retardation is proposed to be due to the notable shape change between the initial, nearly spherical, and the final, strongly deformed, states. A similar scenario is also considered for the 13/2⁺ isomer in ¹⁸¹Hg, suggesting both are cases of shape isomers. The $B (M 2)$ systematics of neutron transitions across the nuclear chart is discussed.
First observation of a shape isomer and a low-lying strongly-coupled prolate band in neutron-deficient semi-magic 187Pb
2022, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Prompt and delayed γ-ray spectroscopy of the neutron-deficient, semi-magic isotope ¹⁸⁷Pb has been performed using the recoil-decay and isomer-decay tagging techniques at the Argonne Gas-Filled Analyzer. A new 5.15(15)-μs isomeric state at only 308 keV above the spherical 3/2⁻ ground state is identified and classified as a shape isomer. A strongly-coupled band is observed on top of the isomer, which is nearly identical to the one built on the prolate 7/2⁻[514] Nilsson state in the isotone ¹⁸⁵Hg. Based on this similarity and on the result of the potential-energy surface calculations, the new isomer in ¹⁸⁷Pb is proposed to originate from the same configuration. The retarded character of the 308-keV (7/2⁻)→3/2 $_{g s}^{-}$ transition with a deduced $B (E 2) = 5.6 (2) \times 10^{- 4}$ W.u. can be well explained by the significant difference between the prolate parent and spherical daughter configurations, leading to the shape isomerism. The excitation energy of the isomer is surprisingly low, being roughly half of the excitation energies of the known 0⁺ intruder bandheads in the neighboring ^186,188Pb isotopes. The combined results of the present work and the previous α-decay and laser spectroscopy studies present evidence for triple shape coexistence at low energy in the negative-parity configurations of ¹⁸⁷Pb, which is well reproduced by the potential-energy surface calculations.
Nuclear Data Sheets for A = 183
2016, Nuclear Data Sheets
Evaluated nuclear structure and decay data for all nuclides with mass number A=183 (Yb, Lu, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Tl, Pb) are presented here. At, Po and Fr have not yet been observed, but for prediction of ground state and/or isomer properties see, e.g., 2015Bh08 (At, Fr), 2013Ba41 (Tl), 2013Ho05 (Po). This evaluation includes structure and decay data information available by 15 April 2015 and supersedes that by R.B. Firestone published in Nuclear Data Sheets 65, 589 (1992) (literature cutoff 9 January 1991), and subsequent revisions by C.M. Baglin for ¹⁸³Au in ENSDF database (literature cutoff 13 March 1999), ¹⁸³Hg in Nuclear Data Sheets 91, 117 (2000) (literature cutoff 25 September 2000), ¹⁸³Tl in Nuclear Data Sheets 95, 49 (2002) (literature cutoff 1 January 2002) and ¹⁸³Pb in ENSDF (literature cutoff 6 January 2003).
Since the prior Nuclear Data Sheets publication of this mass chain: ¹⁸³Yb (2012Ku26) and ¹⁸³Pb (2006An11, 2006Se18, 2007De09, 2009Se13) have been observed; our knowledge of high–spin states has been significantly expanded for ¹⁸³Ta (2009Sh17), ¹⁸³W (1999Sa60), ¹⁸³Re (1998Ha51, 2001Sh41), ¹⁸³Au (2002Jo18, 2005So01) and ¹⁸³Tl (2001Mu26, 2004Ra28); a large amount of new structure information for ¹⁸³W has been obtained from transfer reactions (1997Pr02, 2011Bo09), (n,n'γ) (1993Pr09) and thermal neutron capture (1993Pr09, 1997Pr02, 2011Bo09, 2014Hu02), as well as from the two–photon cascade study by 2005Su29.
Nuclear data sheets for 183Hg
2000, Nuclear Data Sheets
Nuclear structure data pertaining to ¹⁸³Hg have been compiled and evaluated, and incorporated into the ENSDF data file. This evaluation of ¹⁸³Hg supersedes the previous publication (R.B. Firestone, Nuclear Data Sheets 65, 589 (1992) (literature cutoff date 9 January 1991)), and includes literature available by 25 September 2000. The newly incorporated references are: 1992BoZO, 1993Bi17, 1995Au04, 1995La10, 1995Sh04, 1999An10, 1999An36, 1999Ba45, 2000By02.
Identification of 181Hg and shape coexistence in odd-A Hg isotopes
1997, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
In-beam γ-ray transitions in ¹⁸¹Hg, the lightest odd-A Hg isotope known thus far, have been identified from fragment mass-γ and γ-γ coincidence measurements. Five prolate deformed rotational bands were placed in the level scheme. A decoupled band built on the strongly prolate deformed $12^{−} [521]$ ground state was observed up to $292^{−}$ . A $52^{−} [512]$ configuration is suggested for a pair of strongly coupled bands displaying no signature splitting. The other two bands are also signature partner bands. They are populated with the largest intensity and exhibit splitting. They have been associated with the mixed neutron $i_{132}$ orbitals and are proposed to decay to an $i_{132}$ isomeric state associated with an oblate state.

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¹: Fulbright Fellow, University of Calicut, India.

²: On leave from Banares Hindu University, Banares, India.

³: On leave from Institute of Nuclear Physics, Cracow, Poland.

⁴: On leave of absence from Institute of Theoretical Physics, Warsaw University, and Institute of Physics, Warsaw University, Warsaw, Poland.

⁵: On leave of absence from Tata Institute of Fundamental Research, Bombay 400005, India.

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Physics Letters B

Abstract

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Cited by (13)

Odd-even shape staggering and kink structure of charge radii of Hg isotopes by the deformed relativistic Hartree–Bogoliubov theory in continuum

First observation of the decay of the 13/2<sup>+</sup> isomer in <sup>183</sup>Hg and B(M2) systematics of neutron transitions across the nuclear chart

First observation of a shape isomer and a low-lying strongly-coupled prolate band in neutron-deficient semi-magic <sup>187</sup>Pb

Nuclear Data Sheets for A = 183

Nuclear data sheets for <sup>183</sup>Hg

Identification of <sup>181</sup>Hg and shape coexistence in odd-A Hg isotopes