Configuration changes and hindered decays in four- and six-quasiparticle isomers in {sup 178}Ta

Journal Article · Thu Aug 01 04:00:00 EDT 1996 · Physical Review, C

DOI:https://doi.org/10.1103/PhysRevC.54.R459· OSTI ID:286841

Kondev, F G; Dracoulis, G D; Byrne, A P; Kibedi, T; Bayer, S; Lane, G J ^[1]

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1. Department of Nuclear Physics, Research School of Physical Sciences and Engineering, The Australian National University, Canberra ACT 0200 (Australia)

A six-quasiparticle isomer with {ital K}{sup {pi}}=21{sup {minus}}, a half-life of 290(12) ms, and the {pi}{sup 3}{nu}{sup 3} configuration has been identified in the odd-odd nucleus {sup 178}Ta, at an excitation energy of 2902 keV. The rotational bands built on the known {ital K}{sup {pi}}=15{sup {minus}} isomer and on the newly found 16{sup +} four-quasiparticle and 22{sup +} six-quasiparticle states, have also been identified, allowing characterization of the configurations. The 15{sup {minus}} band is predominantly of {pi}{nu}{sup 3} character with a {pi}{sup 3}{nu} admixture. When the mixing is taken into account the excitation energies of the main yrast multi-quasiparticle states can be reproduced. The multi-quasiparticle states observed are related essentially through the addition of the two-quasiparticle component {nu}{sup 2} [6{sup +}] or {pi}{sup 2} [6{sup +}]. Depending on whether the transition between the states involves the change {nu}{sup 2} [6{sup +}] {r_arrow} [0] or {pi}{sup 2} [6{sup +}] {r_arrow} [0], the {ital E}2 hindrance factors for decays between the six- and four-quasiparticle states are relatively large or small. This dependence mimics the pattern observed in the two-quasiparticle core transitions and, because the 15{sup {minus}} isomer is mainly {pi}{nu}{sup 3}, the magnitude sequence is inverted compared to that observed in {sup 176}Ta. {copyright} {ital 1996 The American Physical Society.}

• OSTI ID: 286841
• Journal Information: Physical Review, C, Journal Name: Physical Review, C Journal Issue: 2 Vol. 54; ISSN PRVCAN; ISSN 0556-2813
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
CONFIGURATION
ENERGY
EXCITATION
HALF-LIFE
ISOMERS
ODD-ODD NUCLEI
QUASI PARTICLES
ROTATIONAL STATES
TANTALUM 178