2018 Impact factor 2.481
Hadrons and Nuclei


Eur. Phys. J. A 13, 429-433 (2002)
DOI: 10.1140/epja/iepja1353

Rotational bands and signature inversion phenomena in $\mth{\pi h_{9/2}\otimes
\nu i_{13/2}}$ and $\mth{\pi i_{13/2}\otimes \nu i_{13/2}}$ structures in odd-odd $\chem{^{176}Ir}$

Y.H. Zhang1, M. Oshima2, Y. Toh2, M. Koizumi2, A. Osa2, T. Shizuma2, T. Hayakawa2, M. Sugawara3, H. Kusakari4, T. Morikawa5, S.X. Wen6 and L.H. Zhu6

1  Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, 730000, PRC
2  Japan Atomic Energy Research Institute, Tokai-mura, Ibaraki 319-1195, Japan
3  Chiba Institute of Technology, Narashino, Chiba 275-0023, Japan
4  Chiba University, Inage-ku, Chiba 263-8512, Japan
5  Department of Physics, Kyushu University, Fukuoka 812-81, Japan
6  China Institute of Atomic Energy, Beijing, 102413, PRC

yhzhang@ns.lzb.ac.cn

(Received: 14 December 2001 / Revised version: 18 January 2002 Communicated by D. Schwalm)

Abstract
High-spin states in $\chem{^{176}Ir}$ have been investigated via the $\chem{^{149}Sm}$( 31 P,4n $\gamma $) $\chem{^{176}Ir}$ reaction through excitation functions, X- $\gamma $ and $\gamma $- $\gamma $ coincidence measurements. Four rotational bands have been identified for the first time and their configurations are suggested on the basis of the existing knowledge of band structures in odd-odd nuclei as well as the measured in-band B(M1)/B(E2) ratios. Among the four bands observed, the $\pi h_{9/2}\otimes \nu i_{13/2}$ and $\pi
i_{13/2}\otimes \nu i_{13/2}$ bands exhibit an anomalous signature splitting. The signature inversion point is observed in the former at $
I_{\rm c}=18\hbar $ which is consistent with expectations; this signature inversion spin in the $\pi
i_{13/2}\otimes \nu i_{13/2}$ band may be larger than 25 $\hbar $. The combined effects of Coriolis and p-n residual interactions involved in such an inversion phenomenon have been discussed qualitatively.

PACS
21.10.Re - Collective levels.
23.20.Lv - Gamma transitions and level energies.
27.70.+q - $150 \leq A \leq 189$ .

© Società Italiana di Fisica, Springer-Verlag 2002