Plunger lifetimes and electromagnetic transition strengths in odd 167Yb

Nine lifetimes have been determined for the first time in the 5/2(-)[523] and 5/2(+)[642] bands of Yb-167 by means of Recoil distance Doppler-shift measurements carried out at the Cologne FN tandem. For the data analysis, a dedicated version of the Differential decay curve method was used. The newly deduced transition strengths and the level scheme are reasonably described by the Particle plus triaxial rotor model (PTRM) calculations except for the behavior of the quadrupole collectivity in the two signatures of the 5/2(+)[642] band. The stretched B(E2)'s in the favored signature are appreciably larger than those in the unfavored signature. The effect increases with spin. In the PTRM calculations, the wave functions of the favored signature levels contain larger contribution of low-Omega orbitals from vi(3/2) parentage than those of the unfavored levels. This could selectively increase the deformation of the favored signature band members. If so, rotation and Coriolis interaction would give rise to a dynamic shape coexistence taking place between the two signatures. (C) 2013 Elsevier B.V. All rights reserved.