Decay of high-spin isomers in Os nuclei by barrier penetration

Chowdhury, P.; Fabricius, B.; Christensen, Carl Jørgen; Azgui, F.; Bjørnholm, S.; Borggreen, J.; Holm, Anders; Pedersen, Jens Olaf Pepke; Sletten, G.; Bentley, M. A.; Howe, D.; Mokhtar, A. R.; Morrison, J. D.; Sharpey-Schafer, J.F.; Walker, P. M.; Lieder, R.M.

doi:10.1016/0375-9474(88)90526-x

Cited by 97 publications

(42 citation statements)

References 20 publications

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“…Different theoretical mechanisms have been proposed to explain these abnormally fast decays. The possibility of coupling to collective triaxial states was proposed early [10,11], and systematic calculations of collective tunneling in the γ degree of freedom [12] could successfully reproduce many, although not all, observed lifetimes of direct decay to the ground-state band [13,14]. Tunneling in the spin orientation has been proposed as an alternative mechanism, more suitable to explain decay to bands having intermediate values of K [15].…”

Section: Introductionmentioning

confidence: 99%

Global properties ofKhindrance probed by theγdecay of the warm rotating174W nucleus

Vandone¹,

Leoni²,

Blasi³

et al. 2013

Phys. Rev. C

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The K hindrance to the γ decay is studied in the warm rotating 174 W nucleus, focusing on the weakening of the selection rules of the K quantum number with increasing excitation energy. 174 W was populated by the fusion reaction of 50 Ti (at 217 MeV) on a 128 Te target, and its γ decay was detected by the AGATA Demonstrator array coupled to a BaF 2 multiplicity filter at Laboratori Nazionali di Legnaro of INFN. A fluctuation analysis of γ coincidence matrices gives a similar number of low-K and high-K discrete excited bands. The results are compared to simulations of the γ -decay flow based on a microscopic cranked shell model at finite temperature in which the K mixing is governed by the interplay of Coriolis force with the residual interaction. Agreement between simulations and experiment is obtained only by hindering the E1 decay between low-K and high-K bands by an amount compatible with that determined by spectroscopic studies of K isomers in the same mass region, with a similar trend with excitation energy. The work indicates that K mixing due to temperature effects may play a leading role for the entire body of discrete excited bands, which probes the onset region of K weakening.

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Section: Introductionmentioning

confidence: 99%

Global properties ofKhindrance probed by theγdecay of the warm rotating174W nucleus

Vandone¹,

Leoni²,

Blasi³

et al. 2013

Phys. Rev. C

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“…This restriction is one of the major drawbacks of the method because it limits its applicability to systems where triaxiality does not play an important role. However, many exciting experimental and theoretical phenomena are closely related to the triaxial degree of freedom, for instance: the presence of γ-bands in the low lying energy spectra and γ-softness, shape coexistence and shape transitions in transitional regions [13,[15][16][17][18][19][20]; the lowering of fission barriers along the triaxial path [21][22][23]; the influence of triaxial deformation in the ground state for the mass models [24,25]; triaxiality at high spin [26][27][28]; the observation of K-bands and isomeric states in the Os region [29][30][31]; or some other exotic excitation modes such as wobbling motion and chiral bands [32][33][34].…”

Section: Introductionmentioning

confidence: 99%

Triaxial angular momentum projection and configuration mixing calculations with the Gogny force

2010

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We present the first implementation in the (β, γ) plane of the generator coordinate method with full triaxial angular momentum and particle number projected wave functions using the Gogny force. Technical details about the performance of the method and the convergence of the results both in the symmetry restoration and the configuration mixing parts are discussed in detail. We apply the method to the study of 24 Mg, the calculated energies of excited states as well as the transition probabilities are compared to the available experimental data showing a good overall agreement. In addition, we present the RVAMPIR approach which provides a good description of the ground and gamma bands in the absence of strong mixing.

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“…Walker et al [25] observed in 174 Hf a K ¼ 14 þ , a 4ms isomer that decays to the yrast band 14 þ and a nearby 2-quasiparticle band with reduced hindrance factors of about 5 which they ascribe to the role of Coriolis band mixing. Chowdhury et al [26] ascribed the K breakdown in 182 Os to softness in the triaxiality degree of freedom in this nucleus that allows barrier penetration between the rotation-aligned and deformation-aligned configurations. Sun et al [27] have suggested that significant softness to the triaxiality will occur in 178 Hf, thus both mechanisms for…”

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confidence: 98%

Nuclear structure implications for controlled energy release of isomers

Cline

Hayes

2005

Journal of Modern Optics

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Heavy-ion induced Coulomb excitation has been used to determine level energies and E matrix elements for rotational bands built on isomeric states in 178 Hf. The E matrix elements are consistent with a dramatic increase in K mixing with increasing spin in the ground band, presumably due to Coriolis induced rotation alignment. The spin dependence of the K-distribution for the mixed K ground band states has been deduced. The large K mixing at higher spin provides viable Coulomb excitation paths for stimulated depopulation of high-K isomers in 178 Hf.

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Decay of high-spin isomers in Os nuclei by barrier penetration

Cited by 97 publications

References 20 publications

Global properties ofKhindrance probed by theγdecay of the warm rotating174W nucleus

Global properties ofKhindrance probed by theγdecay of the warm rotating174W nucleus

Triaxial angular momentum projection and configuration mixing calculations with the Gogny force

Nuclear structure implications for controlled energy release of isomers

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