Detailed band structures in 189Hg and 190Hg

doi:10.1016/0375-9474(94)90253-4

Nuclear Physics A

Volume 576, Issue 3, 5 September 1994, Pages 441-476

https://doi.org/10.1016/0375-9474(94)90253-4 Get rights and content

Abstract

The level structures of the ¹⁸⁹Hg and ¹⁹⁰Hg nuclei have been extended considerably from earlier studies by using the ¹⁶⁰Gd(³⁴S, 4n and 5n) reactions in conjunction with an array of twelve Compton suppressed Ge detectors. Eight band structures have been delineated in ¹⁸⁹Hg and ten in ¹⁹⁰Hg. Most bands can be understood within the framework of cranked shell model calculations assuming an oblate collective shape and specific quasiparticle configurations are proposed. There is also some evidence for the onset of triaxiality. In both nuclei level structures which appear to be non-collective in character are interpreted in a band termination picture.

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Nuclear Data Sheets for A=190
2020, Nuclear Data Sheets
The evaluated experimental data are presented and evaluated for 15 known nuclides of mass 190 (Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Tl, Pb, Bi, Po). This work supersedes earlier full evaluations of A=190 by 2003Si05, 1990Si09, 1982Le22 and 1973Sc42. For ¹⁹⁰Hf, only the isotopic identification has been made, with no information about the half-life of the ground state or its decay properties. For ¹⁹⁰Ta, only one excited state as an isomer has been identified, but with no knowledge about its decay properties. For ¹⁹⁰W, ¹⁹⁰Re, ¹⁹⁰Bi and ¹⁹⁰Po, available spectroscopic data are scarce. The decay schemes of ¹⁹⁰Ta, ¹⁹⁰W, ¹⁹⁰Au, ¹⁹⁰Hg, ¹⁹⁰Au isomer decay, ¹⁹⁰Tl (both the activities), ¹⁹⁰Pb, and ¹⁹⁰Bi (both the activities) are considered incomplete by the evaluators. At present, extensive level structures, both the low-spin and high-spin, are known for ¹⁹⁰Os, ¹⁹⁰Ir, ¹⁹⁰Pt, ¹⁹⁰Au, ¹⁹⁰Hg, ¹⁹⁰Tl and ¹⁹⁰Pb, but data for level lifetimes, and γ-ray transition probabilities are generally lacking.
Coexisting shape- and high-K isomers in the shape transitional nucleus 188Pt
2014, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
A high-spin study of the shape transitional nucleus ¹⁸⁸Pt reveals the unusual coexistence of both shape- and K-isomeric states. Reduced $B (E2)$ transition probabilities for decays from these states inferred from the data clearly establish their hindered character. In addition to other excited structures, a rotational band built upon the K isomer is identified, and its configuration has been assigned through an analysis of alignments and branching ratios. The shape evolution with spin in this nucleus has been inferred from both experimental observables and cranking calculations. The yrast positive parity structure appears to evolve from a near-prolate deformed shape through triaxial at intermediate excitation, and eventually to oblate at the highest spins.
Nuclear data sheets for A = 189
2003, Nuclear Data Sheets
Evaluated spectroscopic data for all nuclei with mass number A=189 and corresponding level schemes from radioactive decay and reaction studies are presented. This evaluation contains new extensive spectroscopic data on ¹⁸⁹Os from (n,γ) work; data on ¹⁸⁹Au, ¹⁸⁹Hg and ¹⁸⁹Tl from heavy-ion γ-ray measurements, and band structures. Detailed results of ¹⁸⁹Hg ε- decay and ¹⁸⁹Hg^m ε-decay measurements are also included. The present evaluation supersedes the earlier one by R. B. Firestone (1990Fi02), published in Nuclear Data Sheets 59, 869 (1990).
Nuclear data sheets for A = 190
2003, Nuclear Data Sheets
Magnetic dipole bands in 190Hg: First evidence of excitations across the Z = 82 sub-shell in Hg nuclei
2001, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
An experiment aimed at studying high-spin states in $^{190} Hg$ was performed with the Eurogam II array. The data have revealed the presence of cascades of magnetic dipole transitions with some unexpected properties. Unlike the M1 bands previously observed in the heavier Hg isotopes, these structures have extremely large B(M1)/B(E2) ratios. The observation of a third dipole band with much lower B(M1)/B(E2) values in the same spin/excitation energy regime suggests that the bands may represent configurations occurring in different minima in the potential energy surface. Configuration-dependent Cranked Nilsson–Strutinsky calculations predict the presence of a minimum in the nuclear potential energy surface at a deformation of ε≈0.2, γ≈−90°, occurring when a proton is excited across the Z=82 shell-gap into an h_9/2 orbital. It is suggested that the bands exhibiting anomalously large B(M1)/B(E2) ratios may be associated with this minimum.
Time-decay history of normal-deformation high-spin states in 193,194Hg
1999, Nuclear Physics A
The time evolution of the decay of high-spin, normal deformed structures in ^193,194Hg was studied by measuring, in the Gammasphere array, the Doppler shift attenuation of selected transitions depopulating various bands. The data suggest that a fraction of states feeding selective yrast levels is non-collective in nature and show resemblance to A = 150 nuclei where shape polarizing effects have been linked to particles occupying high-j orbitals.

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¹: Present address: Department of Physics, North Carolina State University, Raleigh, NC 27695, USA.

²: Present address: Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA.

³: Present address: Institute of Nuclear Physics, PL-31342 Cracow, Poland.

⁴: Present address: Physics Department, University of Tennessee, Knoxville, TN 37966, USA.

⁵: Present address: Physics Department, University of Washington, Seattle, WA 98195, USA.

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Nuclear Physics A

Abstract

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Nuclear Data Sheets for A=190

Coexisting shape- and high-K isomers in the shape transitional nucleus <sup>188</sup>Pt

Nuclear data sheets for A = 189

Nuclear data sheets for A = 190

Magnetic dipole bands in <sup>190</sup>Hg: First evidence of excitations across the Z = 82 sub-shell in Hg nuclei

Time-decay history of normal-deformation high-spin states in <sup>193,194</sup>Hg