The decay of a new 18.7 h isomer of 200Au

doi:10.1016/0375-9474(68)90342-4

Nuclear Physics A

Volume 118, Issue 2, 7 October 1968, Pages 361-368

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Abstract

An 18.7±0.5 h isomer of ²⁰⁰Au has been found as a result of bombardments of enriched ¹⁹⁸Pt with 35 MeV α-particles and of enriched ²⁰²Hg with 20 MeV deuterons. The following intense γ-rays were observed in the decay of ^200mAu (relative intensities in parentheses): 181.1±0.4 (73), 255.8±0.3 (96), 367.8±0.3 (100), 498.2±0.4 (95), 579.6±0.4 (100), 759.6±0.4 (90) and 904.5±0.6 keV (11). By the sum-coincidence technique, it was shown that the six strongest γ-rays are in prompt coincidence with each other. It is proposed that in the decay of ^200mAu, the main β-decay branch populates a level in ²⁰⁰Hg at 2642 keV, which de-excites by a cascade of four γ-rays to the known 4⁺ level at 947.3 keV. Isomeric transitions to the ²⁰⁰Au ground state account for less than 4% of the ^200mAu decays.

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Cited by (23)

Recommended Nuclear Structure and Decay Data for A = 200 Isobars
2023, Nuclear Data Sheets
Evaluated nuclear structure and decay data for all nuclei with mass number $A = 200$ (²⁰⁰Os, ²⁰⁰Ir, ²⁰⁰Pt, ²⁰⁰Au, ²⁰⁰Hg, ²⁰⁰Tl, ²⁰⁰Pb, ²⁰⁰Bi, ²⁰⁰Po, ²⁰⁰At, ²⁰⁰Rn, and ²⁰⁰Fr), are presented. All available experimental data are compiled and evaluated, and best values for level and γ-ray energies, quantum numbers, lifetimes, γ-ray intensities and transition probabilities, as well as other nuclear properties, are recommended. Inconsistencies and discrepancies that exist in the literature are discussed. A number of computer codes (https://www-nds.iaea.org/public/ensdf_pgm/) developed by members of the NSDD network were used during the evaluation process. This work supersedes the earlier evaluation by F.G. Kondev and S. Lalkovski (2007Ko42), published in Nuclear Data Sheets 108, 1471 (2007).
Nuclear Data Sheets for A = 200
2007, Nuclear Data Sheets
Nuclear data sheets update for A = 200
1995, Nuclear Data Sheets
Nuclear data sheets for A = 200
1987, Nuclear Data Sheets
Nuclear magnetic moment of 7.8 s 11 2-197mAu and 2.3 d 12- 198mAu
1984, Nuclear Physics, Section A
The technique of nuclear magnetic resonance on oriented nuclei (NMR-ON) has been applied to $^{197m} Au (J^{π} = 112^{−}; T_{12} = 7.8 s) and^{198m} Au (J^{π} = 12^{−}; configuration |(π 112^{−})(v 132)^{+} >_{12}^{−}; T_{12} = 2.3 d)$ in Fe and Ni, the samples being prepared by recoil implantation after (α, xnyp)-induced nuclear compound reactions at E_α = 58–60 MeV. The effective zero-field hyperfine splitting frequencies were measured as $ν (^{197m} Au Ni) = 219.72(4) MHz$ , $ν (^{197m} Au Fe) = ν (^{198m} Au Ni) = 98.40(1) MHz and ν (^{198m} Au Fe) = 425.5(3) MHz$ . With the known for Au in Fe and Ni corrected for hyperfine anomalies the g-factors and magnetic moments are deduced to be $g = (+)1.087(16), μ = (+)5.98(9)μ_{N} for^{197m} Au and g = (+)0.487(7), μ = (+)5.85(9)μ_{N} for^{198m} Au$ . Taking into account the known magnetic properties of other $π 112^{−}$ isomeric states in Ir and Au and of $ν 132^{+}$ states in neighbouring Pt and Hg, the systematics of $π 112^{−}$ magnetic moments and the violation of the additivity of magnetic moments for 12⁻ ^198mAu are discussed.
Nuclear magnetic moment of the 9.7 h 12- isomer 196mAu
1982, Nuclear Physics, Section A
The magnetic hyperfine splitting v_M=|gμ_NB_HF/h| of ^196mAu (j^π=12⁻; configuration ¦(π $112$ ( $v 132^{+})〉_{12}^{−}$ ; $T_{12} = 9.7 h)$ as dilute impurity in Ni has been determined with nuclear magnetic resonance on oriented nuclei as 96.0(2) MHz. With the known hyperfine field B_HF = −264.4(3.9) kG corrected for hyperfine anomalies the g-factor and magnetic moment of ^196mAu are deduced to be |g| = 0.476(7) and |μ| = 5.72(8) μ_N. Taking into account the known magnetic properties of $π 12^{−}$ and $v 132^{+}$ isomeric states in the neighbouring odd Pt, Au and Hg nuclei the structure of the 12⁻ state is discussed.

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^†: Work supported by the U. S. Atomic Energy Commission under Contract At(11-1)-1672.

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Nuclear Physics A

Abstract

References (8)

Nucl. Phys.

Nucl. Phys.

Nucl. Phys.

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Cited by (23)

Recommended Nuclear Structure and Decay Data for A = 200 Isobars

Nuclear Data Sheets for A = 200

Nuclear data sheets update for A = 200

Nuclear data sheets for A = 200

Nuclear magnetic moment of 7.8 s 11 2<sup>-197m</sup>Au and 2.3 d 12<sup>- 198m</sup>Au

Nuclear magnetic moment of the 9.7 h 12<sup>-</sup> isomer <sup>196m</sup>Au