2016/02/29 by Yu-Chun Li, Xiao-Tao He
Physics and Astronomy · #nucl-th
paper · pdf · doi:10.1007/s11433-016-0061-0
published as Sci. China: Phys., Mech. Astron. 59 (2016) 672011 · arXiv admin note: text overlap with arXiv:1208.1156 by other authors
arxiv created 2016/04/20 · arxiv updated 2020/03/10
Experimentally observed ground state band based on the 1/2-[521] Nilsson state and the first exited band based on the 7/2-[514] Nilsson state in the odd-Z nucleus 255Lr are studied by the cranked shell model (CSM) with the paring correlations treated by the particle-number-conserving (PNC) method. This is the first time the detailed theoretical investigations being performed on these rotational bands. Both the experimental kinematic and dynamic moment of inertia (J(1) and J(2)) versus rotational frequency are reproduced quite well by the PNC-CSM calculations. By comparing the theoretical kinematic moment of inertia J(1) with the experimental ones extracted from different spin assignments, the spin 17/2-→13/2- is assigned to the lowest-lying 196.6(5) keV transition of the 1/2-[521] band, and 15/2-→11/2- to the 189(1) keV transition of the 7/2-[514] band, respectively. The proton N=7 major shell is included in the calculations. The intruder of the high-j low-Ω orbitals 1j15/2 (1/2-[770]) at the high spin leads to the band-crossing at ℏω≈0.20 (ℏω≈0.25) MeV for the 7/2-[514] α=-1/2 (α=+1/2) band, and at ℏω≈0.175 MeV for the 1/2-[521] α=-1/2 band, respectively. Further investigations show that the band-crossing frequencies are quadrupole deformation dependent.