摘要
The shape deformation and shape coexistence in ^(74,76) Kr isotopes are investigated within the framework of the proton-neutron interacting boson model(IBM2). By considering the relative energy of the d proton boson to be different from that of the neutron boson, the low-lying energy spectrum is in good agreement with experimental results both qualitatively and quantitatively. In particular, the low-lying 0_2^+ states associated with the shape-coexistence phenomenon are reproduced quite well. The calculated key sensitive quantities of B(E2) transition branch ratios are fairly consistent with the experimental data except for R_4. The predicated deformation parameter is very similar for the ground states in ^(74)Kr and ^(76)Kr, showing good agreement with the experimental result,and the calculated deformation parameter for the second 0^+ state in ^(74)Kr is close to the experimental data. The calculated results of the triaxiality parameter indicated an almost purely prolate shape for the ground state of ^(76)Kr and a mostly prolate shape with a little triaxiality for the ground state of ^(74)Kr. The calculations also show an oblate triaxial shape for the second 0^+ state in ^(76)Kr and maximum triaxiality for the second 0^+ state in ^(74)Kr. These results confirm the importance of the triaxial deformation for the description of such shape coexistence.
The shape deformation and shape coexistence in ^（74,76） Kr isotopes are investigated within the framework of the proton-neutron interacting boson model（IBM2）. By considering the relative energy of the d proton boson to be different from that of the neutron boson, the low-lying energy spectrum is in good agreement with experimental results both qualitatively and quantitatively. In particular, the low-lying 0_2~＋ states associated with the shape-coexistence phenomenon are reproduced quite well. The calculated key sensitive quantities of B（E2） transition branch ratios are fairly consistent with the experimental data except for R_4. The predicated deformation parameter is very similar for the ground states in ^（74）Kr and ^（76）Kr, showing good agreement with the experimental result,and the calculated deformation parameter for the second 0~＋ state in ^（74）Kr is close to the experimental data. The calculated results of the triaxiality parameter indicated an almost purely prolate shape for the ground state of ^（76）Kr and a mostly prolate shape with a little triaxiality for the ground state of ^（74）Kr. The calculations also show an oblate triaxial shape for the second 0~＋ state in ^（76）Kr and maximum triaxiality for the second 0~＋ state in ^（74）Kr. These results confirm the importance of the triaxial deformation for the description of such shape coexistence.
基金
supported by the National Natural Science Foundation of China (Grant Nos. 11475062, 11547312 and 11147148)
