The properties of the low-lying states and the shape coexistence in 98Sr are investigated within the framework of the proton-neutron interacting boson model （IBM2）. By considering the relative energy of the d proton...The properties of the low-lying states and the shape coexistence in 98Sr 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, it is found that the calculated energy levels and the B（E2） transition strengths agree with the experimental data perfectly. Particularly, the second 0＋ state, which is associated with the shape coexistence phenomenon and has the lowest energy E（O＋） among all known even-even nuclei, is reproduced very well. The behavior of the calculated quadrupole shape invariants is consistent with the experimental results.展开更多
Recent experiments open up the possibility to investigate oblate rotation-aligned states and prolate high-K isomers in neutron-rich tungsten isotopes.In the present work,we perform the projected-shell-model calculatio...Recent experiments open up the possibility to investigate oblate rotation-aligned states and prolate high-K isomers in neutron-rich tungsten isotopes.In the present work,we perform the projected-shell-model calculations for A ～ 190 tungsten nuclei.The 190 W results are compared with experimental data.The observed 8 + isomer is assigned as a two-quasiproton K π = 8 + configuration.Low-lying high-K four-quasiparticle states are predicted.Of particular interest is the prediction of the K π = 20 + state in 190,192 W,which may form a long-lived spin trap.In competition with the prolate high-K states,rotational alignment leads to near-yrast collective oblate rotation.展开更多
Inspired by the recent experimental identification of the new isomer with a half-life of （620±150） ns in the very neutron-rich nucleus 180SZr, we apply the projected shell model with axially-deformed bases to d...Inspired by the recent experimental identification of the new isomer with a half-life of （620±150） ns in the very neutron-rich nucleus 180SZr, we apply the projected shell model with axially-deformed bases to discuss possible shapes near the ground state and the nature of the isomer. The structure of the new isomer is investigated by restricting the calculation to prolate and oblate shapes. It is shown that the isomer can be understood as a K-isomer. Meanwhile, the calculation predicts more low-lying high-K configurations, which may be confirmed by future experiments,展开更多
High-spin states in nucleus ^139Pm have been studied using the reaction ^116Cd（^27Al, 4n）^139Pm. Two dipole cascades have been found. Spin and parity assignments were based on the Directional Correlation of Oriented...High-spin states in nucleus ^139Pm have been studied using the reaction ^116Cd（^27Al, 4n）^139Pm. Two dipole cascades have been found. Spin and parity assignments were based on the Directional Correlation of Oriented Nuclei （DCO） ratios and systematic behavior in neighboring odd-proton nuclei. The level structures of ^139Pm are compared with those of the N = 78 isotone ^141Eu in which two dipole bands have been confirmed as magnetic rotational bands. The close similarity between them suggests that the dipole bands in ^139Pm may be magnetic rotational bands.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 11475062,11547312 and 11147148
文摘The properties of the low-lying states and the shape coexistence in 98Sr 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, it is found that the calculated energy levels and the B（E2） transition strengths agree with the experimental data perfectly. Particularly, the second 0＋ state, which is associated with the shape coexistence phenomenon and has the lowest energy E（O＋） among all known even-even nuclei, is reproduced very well. The behavior of the calculated quadrupole shape invariants is consistent with the experimental results.
基金supported by the National Natural Science Foundation of China (Grant No. 10975006)
文摘Recent experiments open up the possibility to investigate oblate rotation-aligned states and prolate high-K isomers in neutron-rich tungsten isotopes.In the present work,we perform the projected-shell-model calculations for A ～ 190 tungsten nuclei.The 190 W results are compared with experimental data.The observed 8 + isomer is assigned as a two-quasiproton K π = 8 + configuration.Low-lying high-K four-quasiparticle states are predicted.Of particular interest is the prediction of the K π = 20 + state in 190,192 W,which may form a long-lived spin trap.In competition with the prolate high-K states,rotational alignment leads to near-yrast collective oblate rotation.
基金supported by the National Natural Science Foundation of China(Grant Nos.11305059,11275067,11135005,11275068 and 11475062)the National Program on Key Basic Research Project(Grant No.2013CB834401)the Open Project Program of State Key Laboratory of Theoretical Physics,Institute of Theoretical Physics,Chinese Academy of Sciences(Grant No.Y5KF141CJ1)
文摘Inspired by the recent experimental identification of the new isomer with a half-life of （620±150） ns in the very neutron-rich nucleus 180SZr, we apply the projected shell model with axially-deformed bases to discuss possible shapes near the ground state and the nature of the isomer. The structure of the new isomer is investigated by restricting the calculation to prolate and oblate shapes. It is shown that the isomer can be understood as a K-isomer. Meanwhile, the calculation predicts more low-lying high-K configurations, which may be confirmed by future experiments,
基金Supported by Major State Basic Research Development Program of China (2007CB815005)National Natural Science Foundation of China (10825522,10735010,10775158)and Chinese Academy of Sciences
文摘High-spin states in nucleus ^139Pm have been studied using the reaction ^116Cd（^27Al, 4n）^139Pm. Two dipole cascades have been found. Spin and parity assignments were based on the Directional Correlation of Oriented Nuclei （DCO） ratios and systematic behavior in neighboring odd-proton nuclei. The level structures of ^139Pm are compared with those of the N = 78 isotone ^141Eu in which two dipole bands have been confirmed as magnetic rotational bands. The close similarity between them suggests that the dipole bands in ^139Pm may be magnetic rotational bands.
