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
We investigate properties of the low-lying energy states for 76Ge within the framework of the proton-neutron interacting model IBM2,considering the validity of the Z=38 subshell closure 88Sr50 as a doubly magic core.B...We investigate properties of the low-lying energy states for 76Ge within the framework of the proton-neutron interacting model IBM2,considering the validity of the Z=38 subshell closure 88Sr50 as a doubly magic core.By introducing the quadrupole interactions among like bosons to the IBM2 Hamiltonian,the energy levels for both the ground state andγbands are reproduced well.Particularly,the doublet structure of theγband and the energy staggering signature fit the experimental data correctly.The ratios of B(E2)transition strengths for some states of theγband,and the g factors of the 2^(+)_(1),2^(+)_(2) states are very close to the experimental data.The calculation result indicates that the nucleus exhibiting rigid triaxial deformation in the low-lying states can be described rather well by the IBM2.展开更多
We investigate the properties of the low-lying states and the relevant shape dynamics of ^98 Mo within the frame- work of the proton-neutron interacting boson model （IBM2）. By considering the relative energy of the ...We investigate the properties of the low-lying states and the relevant shape dynamics of ^98 Mo within the frame- work 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 bosons, the low-lying levels and the key observable B（E2） transition branching ratios are calculated. The characteristic feature of the energy spectrum and the most crucial available structure indicator indicate that the substantial mixing between the spherical-vibrational and γ-unstable shapes in 9SMo. The calculation results of the overall deformation in ^98Mo are almost the same for both the ground and the first excited 02^＋ states, showing a weak deformation. While the triaxiality parameter indicates that the mostly triaxial shape with some oblate for the ground state, and the triaxial shape with some prolate for the excited 02^＋ state, being equilibrium shapes of spherical-vibrational and γ-unstable in ^98 Mo.展开更多
Based on the generalized boson-fermion expansion technique,a microscopic sdg IBM plus two-quasiparticle approach is proposed to investigate the high spin states,The effect of the 8-boson on the back-bending phenomenon...Based on the generalized boson-fermion expansion technique,a microscopic sdg IBM plus two-quasiparticle approach is proposed to investigate the high spin states,The effect of the 8-boson on the back-bending phenomenon and the states below 2 MeV are discussed for the Ba isotopes.展开更多
The properties of the low-lying energy states for the l00 Mo isotope is investigated within the framework of the proton-neutron interacting model IBM2. By considering the relative energy of the d proton boson to be di...The properties of the low-lying energy states for the l00 Mo isotope is investigated within the framework of the proton-neutron interacting model IBM2. By considering the relative energy of the d proton boson to be different from that of the neutron boson and taking into account the dipole interacting among like-boson Lπ·Lπ and Lπ·Lπ, the low-lying energy spectrum is reproduced well. Particularly, the relative position of the energies for 2＋1, 0＋2, 2＋2 and 4＋1 states shifted correctly fit the experimental data. The electromagnetic properties, including the key observable B（E2） reduced transition branching ratios and the E2 reduced matrix elements of the experimental data, are well described. Our calculations show possible shape coexistence in the l00Mo nucleus.展开更多
The characteristics of the lowest mixed-symmetry states 2＋msand 1＋ms for132Xe,134 Ba and136Ce in the even-even N = 78 isotones are investigated within the framework of the IBM2 model. The lowest mixed-symmetry stat...The characteristics of the lowest mixed-symmetry states 2＋msand 1＋ms for132Xe,134 Ba and136Ce in the even-even N = 78 isotones are investigated within the framework of the IBM2 model. The lowest mixed-symmetry state 2＋mslevels for both a single isolated state in132 Xe and136Ce and a fragmented state in134 Ba are reproduced by the predictions. The agreement between the IBM2 calculation and the experimental values is good for the B（E2）and B（M1） transition probabilities both quantitatively and qualitatively. The predicted summed B（M1） strength follows the experimental data, remaining nearly constant as a function of proton number along the chain of the N =78isotones.展开更多
We have investigated the structure evolution of the ^124-134Xe isotopic chain in the framework of the proton-neutron interacting model IBM2. The positive parity spectra of the ground state, quasi-β and quasi-γ bands...We have investigated the structure evolution of the ^124-134Xe isotopic chain in the framework of the proton-neutron interacting model IBM2. The positive parity spectra of the ground state, quasi-β and quasi-γ bands are reproduced well. The staggering in ^124-130Xe are almost completely removed and the ？ band agree well with the experiment data, even for the high-spin quasi-3 states. The key quantities of the collective structure evolution, including level energies, the B（E2） transition branching ratios, and the M1 excitations to 11^＋ mixer-symmetry states are analyzed by comparing with the experimental data. The parameters for representation of the Oπν（6） and SUπν^＊（3） features in isotopes are examined. Both experimental data and theoretical results show that the shape phase transition of ^124-134Xe isotopic chain is from the SUπν^＊ （3） （triaxial rotation） to the Uπν（5） （vibration motion） with a considerable constituent of the Oπν（6） symmetry （γ-unstable rotation）, where the shape phase transition rapidly takes place between the neutron number N = 76 and N = 78.展开更多
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 t...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.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 under Grant No 11075052the Natural Science Foundation of Zhejiang Province under Grant No KY6100135.
文摘We investigate properties of the low-lying energy states for 76Ge within the framework of the proton-neutron interacting model IBM2,considering the validity of the Z=38 subshell closure 88Sr50 as a doubly magic core.By introducing the quadrupole interactions among like bosons to the IBM2 Hamiltonian,the energy levels for both the ground state andγbands are reproduced well.Particularly,the doublet structure of theγband and the energy staggering signature fit the experimental data correctly.The ratios of B(E2)transition strengths for some states of theγband,and the g factors of the 2^(+)_(1),2^(+)_(2) states are very close to the experimental data.The calculation result indicates that the nucleus exhibiting rigid triaxial deformation in the low-lying states can be described rather well by the IBM2.
基金Supported by the National Natural Science Foundation of China under Grant No 11475062the Natural Science Foundation of Zhejiang Province under Grant No Y6100135
文摘We investigate the properties of the low-lying states and the relevant shape dynamics of ^98 Mo within the frame- work 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 bosons, the low-lying levels and the key observable B（E2） transition branching ratios are calculated. The characteristic feature of the energy spectrum and the most crucial available structure indicator indicate that the substantial mixing between the spherical-vibrational and γ-unstable shapes in 9SMo. The calculation results of the overall deformation in ^98Mo are almost the same for both the ground and the first excited 02^＋ states, showing a weak deformation. While the triaxiality parameter indicates that the mostly triaxial shape with some oblate for the ground state, and the triaxial shape with some prolate for the excited 02^＋ state, being equilibrium shapes of spherical-vibrational and γ-unstable in ^98 Mo.
基金The project supported by the National Natural Science Foundation of China
文摘Based on the generalized boson-fermion expansion technique,a microscopic sdg IBM plus two-quasiparticle approach is proposed to investigate the high spin states,The effect of the 8-boson on the back-bending phenomenon and the states below 2 MeV are discussed for the Ba isotopes.
基金supported by the National Natural Science Foundation of China(Grant No.11075052)the Natural Science Foundation of Zhejiang Province(Grant No.KY6100135)
文摘The properties of the low-lying energy states for the l00 Mo isotope is investigated within the framework of the proton-neutron interacting model IBM2. By considering the relative energy of the d proton boson to be different from that of the neutron boson and taking into account the dipole interacting among like-boson Lπ·Lπ and Lπ·Lπ, the low-lying energy spectrum is reproduced well. Particularly, the relative position of the energies for 2＋1, 0＋2, 2＋2 and 4＋1 states shifted correctly fit the experimental data. The electromagnetic properties, including the key observable B（E2） reduced transition branching ratios and the E2 reduced matrix elements of the experimental data, are well described. Our calculations show possible shape coexistence in the l00Mo nucleus.
基金Supported by National Natural Science Foundation of China(11475062)Natural Science Foundation of Zhejiang Province,China(KY6100135)
文摘The characteristics of the lowest mixed-symmetry states 2＋msand 1＋ms for132Xe,134 Ba and136Ce in the even-even N = 78 isotones are investigated within the framework of the IBM2 model. The lowest mixed-symmetry state 2＋mslevels for both a single isolated state in132 Xe and136Ce and a fragmented state in134 Ba are reproduced by the predictions. The agreement between the IBM2 calculation and the experimental values is good for the B（E2）and B（M1） transition probabilities both quantitatively and qualitatively. The predicted summed B（M1） strength follows the experimental data, remaining nearly constant as a function of proton number along the chain of the N =78isotones.
基金Supported by the National Natural Science Foundation of China under Grant No.11075052the Natural Science Foundation of Zhejiang Province under Grant No.KY6100135
文摘We have investigated the structure evolution of the ^124-134Xe isotopic chain in the framework of the proton-neutron interacting model IBM2. The positive parity spectra of the ground state, quasi-β and quasi-γ bands are reproduced well. The staggering in ^124-130Xe are almost completely removed and the ？ band agree well with the experiment data, even for the high-spin quasi-3 states. The key quantities of the collective structure evolution, including level energies, the B（E2） transition branching ratios, and the M1 excitations to 11^＋ mixer-symmetry states are analyzed by comparing with the experimental data. The parameters for representation of the Oπν（6） and SUπν^＊（3） features in isotopes are examined. Both experimental data and theoretical results show that the shape phase transition of ^124-134Xe isotopic chain is from the SUπν^＊ （3） （triaxial rotation） to the Uπν（5） （vibration motion） with a considerable constituent of the Oπν（6） symmetry （γ-unstable rotation）, where the shape phase transition rapidly takes place between the neutron number N = 76 and N = 78.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11475062, 11547312 and 11147148)
文摘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.
