K-forbidden isomeric transition in 130Ba

doi:10.1016/0375-9474(69)90563-6

Nuclear Physics A

Volume 133, Issue 3, 25 August 1969, Pages 648-652

https://doi.org/10.1016/0375-9474(69)90563-6 Get rights and content

Abstract

The 8.8 msec isomeric state of ¹³⁰Ba was produced in the reaction ¹²²Sn(¹²C, 4n). It decays by a cascade of 4 transitions to the ground state. Delayed gamma-rays were measured with a Ge(Li) detector, conversion electrons with a magnetic beta-ray spectrometer. Multipolarities were deduced from intensity relations of K-conversion electron lines. The following results were obtained: 355.5 keV (assumed E2), 543.5 keV (E2), 690.0 keV (E2), 881.3 keV (M2). The isomeric state has J^π=8⁻ and decays by the 881.3 keV transition to the 6⁺ state of the ground state rotational band. The large hindrance factor F ≈ 10⁷ s.p.u. is typical for a K-forbidden transition in a deformed nucleus. Possible two-quasiparticle configurations for the isomeric state are discussed.

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Cited by (25)

g-factor and quadrupole moment of the isomeric state in 131La: Signature for a weakly-deformed magnetic rotational band head
2017, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
The g-factor and the static quadrupole moment of a magnetic rotational band head ${\frac{21}{2}}^{-}$ at 2121 keV in ¹³¹La have been determined by means of the time-differential perturbed angular distribution technique. The measured value of the g-factor, $+ 1.060 (4)$ , is in agreement with the theoretical value for a three quasi-proton, $π^{3} {{\frac{11}{2}}^{-} [505] \otimes {\frac{5}{2}}^{+} [422] \otimes {\frac{5}{2}}^{+} [413]}$ Nilsson configuration assignment. The observed spectroscopic quadrupole moment ratio, $\frac{Q_{s} ({\frac{21}{2}}^{-},^{131} La)}{Q_{s} ({\frac{19}{2}}^{-},^{137} La)} = 0.457 (4)$ , supports the collective oblate shape $(γ \sim - 60 °)$ with quadrupole deformation $β_{2} < 0.07$ . The half-life of the ${\frac{21}{2}}^{-}$ state, 37.2(1) ns, is re-measured with better accuracy.
Character of an 8- isomer of 130Ba
2002, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
The static moments and isomer shift of the J^π=K^π=8⁻ isomeric state in $^{130}_{56} Ba$ have been measured using the technique of collinear laser spectroscopy. The isomer has been found to have a magnetic dipole moment of −0.043(28) μ_N and a static quadrupole moment of +2.77(30) b. These values have been used to assign the state as a two neutron $72^{+} [404]⊗ 92^{−} [514]$ configuration corresponding to a prolate shape. The half-life of the isomer has been confirmed as 9.54(14) ms. The change in the mean square charge radius was found to be 〈r²〉^130m−〈r²〉^130g–s=−0.0473(30) fm².
Nuclear data sheets for A = 130
2001, Nuclear Data Sheets
Abstract: Nuclear spectroscopic information for known nuclides of mass number 130 (Ag,Cd,In,Sn,Sb,Te,I,Xe,Cs,Ba, La,Ce,Pr,Nd,Pm,Sm) has been evaluated and presented together with adopted energies, Jp, and decay modes of levels in these nuclei. No data are yet available for excited states in ¹³⁰Ag and ¹³⁰Pm. This evaluation supersedes earlier (1989Se13,1974Hi08) Nuclear Data Sheets for A=130. In the opinion of the evaluator the decay schemes of ¹³⁰In, ¹³⁰Sn, ¹³⁰Sb and ¹³⁰Pr nuclides are not well established. The identification of ¹³⁰Ag isotope is only tentative. The ground state and possible low-lying isomer of ¹³⁰Pr are still not established in energy and Jp assignment. Search (by 1983La27) for proton decay from ¹³⁰Eu decay proved negative, thus ¹³⁰Eu isotope remains unidentified.
High-K bands and oblate-prolate coexistence in 134Nd
1997, Nuclear Physics A
Three bands consisting of dipole M1 and quadrupole E2 crossover transitions have been identified in ¹³⁴Nd using the GASP array and the ¹¹⁰Pd(²⁸Si, 4n) reaction at 130 MeV. Calculations with the projected shell model are used to assign configurations to the different bands and to infer their K-composition. The properties of the band built on the I^π = 8⁻ isomer confirm the previously assigned two-quasineutron [404] $72^{+} ⊗ [514] 92^{−}$ configuration of the isomeric state. The other two bands are interpreted as coexisting prolate and oblate four-quasiparticle configurations.
Nuclear data sheets for A = 130
1989, Nuclear Data Sheets
Decoupling effects in the light mass barium isotopes
1976, Nuclear Physics, Section A
High spin states in ^{126, 128, 132}Ba nuclei have been populated by (HI, xn) reactions and coincidence spectra, angular distribution and polarization of the deexcitation gammas have been used to determine the spins, parities, and decay schemes for these states. The ground-state rotational band in ¹²⁶Ba is strongly excited up to I = 16⁺ and possibly 18⁺. A marked back-bend occurs at the yrast 12⁺ state and a second nearby 12⁺ state appears to be a continuation of the ground-state band. An odd spin negative parity band with spins between 7⁻ and 15⁻ also was strongly excited. Similar behavior is observed in ¹²⁸Ba while a more complicated spectrum is excited in ¹³²Ba. Two-quasiparticle-plus-rotor band mixing calculations have been performed. The observed high spin behavior in ^{126, 128}Ba is well reproduced by these calculations, demonstrating the importance of decoupling of two quasiparticles in these nuclei.

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Nuclear Physics A

Abstract

References (9)

preprint JINR

Phys. Lett.

Usp. Fiz. Nauk

preprint JINR E6-4278

Cited by (25)

g-factor and quadrupole moment of the isomeric state in <sup>131</sup>La: Signature for a weakly-deformed magnetic rotational band head

Character of an 8<sup>-</sup> isomer of <sup>130</sup>Ba

Nuclear data sheets for A = 130

High-K bands and oblate-prolate coexistence in <sup>134</sup>Nd

Nuclear data sheets for A = 130

Decoupling effects in the light mass barium isotopes