Eur. Phys. J. A (2015) 51: 60
https://doi.org/10.1140/epja/i2015-15060-9

Regular Article - Experimental Physics

Reinvestigation of the collective band structures in odd-odd ¹³⁸Pm nucleus

¹ Department of Physics, Tsinghua University, 100084, Beijing, People’s Republic of China
² Department of Physics, Royal Institute of Technology, 10691, Stockholm, Sweden
³ Collaborative Innovation Center of Quantum Matter, Beijing, China
⁴ China Institute of Atomic Energy, 102413, Beijing, China

^* e-mail: xiaozg@tsinghua.edu.cn

Received: 21 August 2014
Revised: 25 April 2015
Accepted: 6 May 2015
Published online: 25 May 2015

Abstract

The high-spin states in the odd-odd ¹³⁸Pm nucleus have been reinvestigated via the ¹²⁴Te(¹⁹F, 5n) reaction at the beam energy of 103 MeV. Most of the known transitions and levels are confirmed. A number of bands are revised and one new band has been established. For the yrast πh _11/2⊗νh _11/2 band based on 8⁺ state, no evidence supporting the occurence of signature inversion is found. The experimental and theoretical B(M1)/B(E2) ratios have been calculated for band (2), which support the πg _7/2[413]5/2⁺ ⊗ νh _11/2[514]9/2⁻ Nilsson configuration assignment. Four bands with ΔI = 2 transitions are tentatively assigned as doubly decoupled bands. The other three bands are proposed as oblate-triaxial bands. The possible configuration assignments for these bands are also discussed under the calculations of total Routhian surface and particle-rotor model.