Prolate deformation in the 187,189Bi isotopes
DAPNIA/SPhN CEA-Saclay, 91191, Gif-sur-Yvette Cedex, France
2 JYFL, University of Jyväskylä, Jyväskylä, Finland
3 Department of Physics, University of Liverpool, Liverpool, UK
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Prompt and delayed gamma-ray spectroscopy of very neutron-deficient bismuth isotopes 187, 189Bi has been performed using the recoil decay tagging method. A rotational band has been observed in 189Bi and is interpreted as a complete decoupling of a single proton from the deformed lead core. The results for 187Bi suggest a similar structure and coupling scheme. This study gives the first evidence for a prolate band in a light bismuth nucleus and confirms the prolate character of the low-lying rotational band observed in the core nuclei 188Pb and 186Pb.
© Società Italiana di Fisica and Springer-Verlag, 2004