Eur. Phys. J. A (2004) 19: 11-23
https://doi.org/10.1140/epja/i2003-10106-3

Configuration-dependent bands in ¹⁶⁹Re

¹ Institute of Modern Physics, Chinese Academy of Sciences, 730000, Lanzhou, PRC
² Japan Atomic Energy Research Institute, 319-1195, Ibaraki, Tokai, Japan
³ Department of Technical Physics and MOE Key Laboratory, Peking University, 100871, Beijing, PRC
⁴ Chiba Institute of Technology, 275-0023, Chiba, Narashino, Japan

^* e-mail: zxh@impcas.ac.cn

Abstract

High-spin states in ¹⁶⁹Re were studied and resulted in the identification of a strongly coupled band based on the 9/2^-[514] Nilsson state and a decoupled band built on the h _9/2 1/2^-[541] intruder proton orbit. The cranked-shell-model calculations present configuration-dependent deformations that can explain the different band crossing frequencies. The 9/2^-[514] band in ¹⁶⁹Re shows the largest signature splitting at low spin among the known odd-mass Re isotopes. After the alignment of a pair of i _13/2 neutrons, the phase of the splitting is inverted with a significantly reduced amplitude. For the 9/2^-[514] bands in light odd-A Re isotopes, the signature splitting of the Routhians and its relation with the signature dependence of M1 transition matrix elements are investigated in connection with the deviation of nuclear shape from axial symmetry, suggesting an appreciable negative deformation for the very neutron-deficient odd-A Re isotopes. Additionally, a three-quasipariticle band was observed and assigned to be built likely on the configuration.