The β-decays of neutron-rich carbon,nitrogen and fluorine isotopes have been sys-tematically studied using the OXBASH shell Model.In the psd,spsd and spsdpf model space,we use the W BP interaction to calculate the half-lives and neutron emission probabilities of neutron-rich carbon and nitrogen isotopes,respectively.With the USD (W) and CW interactions,we calculate the half-lives and neutron emission probabilities of neutron-rich fluorine isotope in the sd model space,respectively.The calculated half-lives and neutron emission probabilities repro-duce recent experimental data very well.It seems to show that the particles of the neutron-rich carbon and nitrogen isotopes are mainly excited in the spsd space.The β-decay of 21N to the neutron bound states in 21O is mostly the first forbidden transition which makes the neutron emission probability increase.The theoretical calculation of β-decay of 25F to 25Ne with CW interaction shows that CW interaction is better than USD interaction.
Using the single particle states and the residual interaction derived from the relativistic point-coupling model with the PC-F1 parameter set,the second-order core polarization corrections to nuclear magnetic moments of LS closed shell nuclei ±1 nucleon with A = 15,17,39 and 41 are studied and compared with previous non-relativistic results.It is found that the second-order corrections are significant.With these corrections,the isovector magnetic moments of the concerned nuclei are well reproduced,especially those for A = 17 and A = 41.
High-spin states in 157yb have been populated in the 144Sm(16O, 3n)157yb fusion-evaporation reaction at a beam energy of 85 MeV, and two rotational bands have been established for the first time. Within the framework of the triaxial particle-rotor model, the energy spectra and single-particle configurations of 157yb are investigated. The calculated energy spectra agree well with the experimental data. The newly observed vf7/2 band, and the previously known vi13/2 band in 157yb, are also discussed by means of Total-Routhian-Surface methods. The structural characters observed in 157Yb provide evidence for the shape coexistence of three distinct shapes: prolate, triaxial and oblate. At higher spins, both the vf7/2 band and the vi13/2 band in 157yb undergo a shape evolution with sizable alignments occurring.
The potential energy surfaces of even-even 142-156Ba are investigated in the constrained reflectionasymmetric relativistic mean-field approach with parameter set PK1. It is shown that for the ground states, 142Ba is near spherical,156Ba well quadrupole-deformed, and in between 144-154Ba octupole deformed. In particular, the nuclei 148,150Ba with N=92, 94 have the largest octupole deformations. By including the octupole degree of freedom, energy gaps N = 88, N = 94 and Z = 56 near Fermi surfaces for the singleparticle levels in 148Ba with β2 ～ 0.26 and β3 ～ 0.17 are found. Furthermore, the performance of the octupole deformation driving pairs (ν2f7/2, ν1i13/2) and (π2d5/2, π1h11/2) is demonstrated by analyzing the singleparticle levels near Fermi surfaces in 148Ba.
