Theoretical calculations have been performed for the ν9/2+[624](i13/2) and ν7/2-[503](f7/2) bands of 185Pt in the framework of particle-rotor model. The band properties of signature splitting and configuration mixin...Theoretical calculations have been performed for the ν9/2+[624](i13/2) and ν7/2-[503](f7/2) bands of 185Pt in the framework of particle-rotor model. The band properties of signature splitting and configuration mixing have been analyzed. The level energy and signature splitting before the band crossing can be well interpreted by introducing triaxiality. The positive-parity yrast band is pro posed to be dominated by the ν9/2+[624](i13/2) component, while the negative-parity band shows strong mixing of ν7/2-[503](f7/2) and ν9/2-[505](h9/2) configurations.展开更多
AI=2 staggering in superdefonned nuclei has been investigated by a perturbed particle-rotor model, of which all observed features are reproduced in the calculations. It is pointed out that the C4symmetry in Hamiltonia...AI=2 staggering in superdefonned nuclei has been investigated by a perturbed particle-rotor model, of which all observed features are reproduced in the calculations. It is pointed out that the C4symmetry in Hamiltonian is not the only cause of AI=2 staggering. This model can be used to make a fit to the experimental data in odd-A superdeformed nuclei.展开更多
Energy level statistics of a system consisting of six particles interacting by delta force in a two- model coupled with a deformed core is studied in particle-rotor model. For single- shell and two- shell the exact ...Energy level statistics of a system consisting of six particles interacting by delta force in a two- model coupled with a deformed core is studied in particle-rotor model. For single- shell and two- shell the exact energies for our statistical analysis are obtained from a full diagonalization of the Hamiltonian, while in two- case the configuration truncation is used. The nearest-neighbor distribution of energy levels and spectral rigidity are studied as the function of spin. The results of single- shell are compared with those in two- case. It is showed that the system becomes more regular when single- space is replaced by two- shell although the basis size of the configuration space is unchanged. The degree of chaoticity of the system, however, changes slightly when configuration space is enlarged by extending single- shell to two- shell .展开更多
The chaotic properties for six particles interacting by a monopole pairing force in a two-j shell model coupled with a deformed core are studied in the frame of particle-rotor model. The nearest-neighbor distribution ...The chaotic properties for six particles interacting by a monopole pairing force in a two-j shell model coupled with a deformed core are studied in the frame of particle-rotor model. The nearest-neighbor distribution of energy levels and spectral rigidity in the two-j shell are compared with those in the single-j case. The results show that the system is more regular in the two-j model than that in the single-j case.展开更多
High-spin states in 157Yb have been populated in the 144Sm（160, 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 framewo...High-spin states in 157Yb have been populated in the 144Sm（160, 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.展开更多
-By using particle-rotor model,the configuration of the superderformed(SD)bands in odd-A Hg nuclei is analysed.It is shown that the electromagnetic transitionproperties of the SD bands can be used to further identify ...-By using particle-rotor model,the configuration of the superderformed(SD)bands in odd-A Hg nuclei is analysed.It is shown that the electromagnetic transitionproperties of the SD bands can be used to further identify the configuration.展开更多
Identical superdeformed bands in <sup>191</sup>Au and <sup>191</sup>Hg have been investigated byusing particle-rotor model within the framework of the BCS （Bardeen-Cooper-Schrieffer） pairing ...Identical superdeformed bands in <sup>191</sup>Au and <sup>191</sup>Hg have been investigated byusing particle-rotor model within the framework of the BCS （Bardeen-Cooper-Schrieffer） pairing correlation.The identity in the γ-transition energies in these bandsshows that the properties of specific individual orbitals may be important to understandidentical bands.展开更多
Using the particle-rotor model,some features of superdeformed bands builtupon j<sub>15</sub> orbitals have been investigated.An excellent agreement between the caleu-lated and observed transition energies,...Using the particle-rotor model,some features of superdeformed bands builtupon j<sub>15</sub> orbitals have been investigated.An excellent agreement between the caleu-lated and observed transition energies,kinematic and dynamic moments of inertiaof Hg（bl）is obtained.展开更多
Superdeformed bands of <sup>193</sup>TI are analyzed by using particle-rotor model inconnection with experimental data,considering the possible occurrence of triaxialshape.It is investigated that γ-transi...Superdeformed bands of <sup>193</sup>TI are analyzed by using particle-rotor model inconnection with experimental data,considering the possible occurrence of triaxialshape.It is investigated that γ-transition energies and dynamic moments of inertia de-pend on γ-deformation and energy gap.展开更多
Progress in the studies of chirality in atomic nuclei at iThemba LABS is reviewed.New regions of chirality,around mass 80 and 190 have been discovered using the AFRODITE array,specifically in the nuclei^(74)As,^(78,80...Progress in the studies of chirality in atomic nuclei at iThemba LABS is reviewed.New regions of chirality,around mass 80 and 190 have been discovered using the AFRODITE array,specifically in the nuclei^(74)As,^(78,80,82)Br,^(81)Kr,and^(193,194,198)Tl.Many phenomena have been observed,including multiple chiral bands in the same nucleus,the coexistence of octupole correlations and nuclear chirality,and the coexistence of pseudo spin and nuclear chirality.The best example of chiral degeneracy to date was found in ^(194)Tl.The level scheme of ^(106)Ag has been revisited and interpreted in terms of two-and four-quasiparticle bands.Investigations using the particle-rotor model have shown that the fingerprints of chirality in the two-quasiparticle system only can occur in an idealised model description.For systems with a higher number of quasiparticles,the calculations showed that nuclear chirality can persist.展开更多
Wobbling motion in a system comprising a triaxial rotor and a single quasiparticle is studied employing the particle-rotor model.The energy spectra,wobbling frequencies,electromagnetic transition probabilities,g-facto...Wobbling motion in a system comprising a triaxial rotor and a single quasiparticle is studied employing the particle-rotor model.The energy spectra,wobbling frequencies,electromagnetic transition probabilities,g-factors,angular momentum components,spin coherent state maps,and static quadrupole moments are investigated.These investigations were conducted with regard to the Fermi surface transitioning from the lowest h_(11/2) orbit to the highest one.As the Fermi surface increases,notable transformations occur in the wobbling mode.Initially,the mode exhibits a transverse revolution around the short axis of the nucleus.However,as the Fermi surface continues to increase,the mode gradually shifts to a longitudinal revolution around the intermediate axis.Eventually,it transitions to a transverse revolution around the long axis.Notably,the stability of the long axis transverse mode diminishes relative to its counterpart along the short axis as the total angular momentum increases atγ=20∘.展开更多
High-spin states in 161Er have been studied experimentally via the 150Nd(16O, 5n) reaction at a beam energy of 86 MeV. Three rotational bands built on the 5/2+[642], 3/2-[521], and 11/2-[505] configurations have been ...High-spin states in 161Er have been studied experimentally via the 150Nd(16O, 5n) reaction at a beam energy of 86 MeV. Three rotational bands built on the 5/2+[642], 3/2-[521], and 11/2-[505] configurations have been extended up to high-spin states, and particularly, the α = -1/2 branch of the ground state 3/2-[521] band has been revised significantly. It is found that signature inversion occurs in the 3/2-[521] band after the band crossing in 161Er. The systematics of the signature inversion associated with the 3/2-[521] configuration in the rare-earth region is discussed. The band properties are analyzed within the framework of a triaxial particle-rotor model, and a triaxial deformation is proposed to the 3/2-[521] band.展开更多
Through particle-rotor model, band structure of superdeformed bands in odd-A Hg nuclei is analysed. An overall and excellent agreement between the calculated and observed kinematic and dynamic moments of inertia is ob...Through particle-rotor model, band structure of superdeformed bands in odd-A Hg nuclei is analysed. An overall and excellent agreement between the calculated and observed kinematic and dynamic moments of inertia is obtained. The electromagnetic transition properties of SD bands can be used to identify the configuration with certainty.展开更多
High-spin levels of ^189Pt have been studied with the in-beam T-spectroscopy method via the ^176Yb（^18O,5n） reaction at the beam energies of 88 and 95 MeV. The previously known ＂vi-1 13/2 band has been confirmed, a...High-spin levels of ^189Pt have been studied with the in-beam T-spectroscopy method via the ^176Yb（^18O,5n） reaction at the beam energies of 88 and 95 MeV. The previously known ＂vi-1 13/2 band has been confirmed, and its unfavored signature branch extended up to the 31/2^＋ state. Within the framework of the triaxial particle-rotor model, the vi-1 13/2 band is suggested to be associated with the 11/2[615] configuration, and to have triaxial deformation.展开更多
The positive-parity signature partner bands in^(103,105)Pd and^(109)Cd nuclei are investigated using the classical particle-rotor model.Based on the systematic study of neighbouring nuclei,the signature partner bands ...The positive-parity signature partner bands in^(103,105)Pd and^(109)Cd nuclei are investigated using the classical particle-rotor model.Based on the systematic study of neighbouring nuclei,the signature partner bands of ^(105)Pd are assigned to theπ(g^(-4)_(9/2))■ν(g7/2h^(2)_(11/2))configuration,and this assignment is also supported by the present calculations.Furthermore,the calculated$B(E2)$values of such bands of ^(105)Pd reproduce the experimental values well and exhibit a decrease with increasing angular momentum,suggesting that these two bands may originate from antimagnetic rotation.Similar signature partner bands are also found in the neighboring^(103)Pd and^(109)Cd nuclei.The properties of both bands are in general agreement with the fingerprints of antimagnetic rotation,and thus the signature partner bands of^(103)Pd and^(109)Cd are suggested to be candidates for the multiple antimagnetic rotational bands of ^(105)Pd.In addition,the evolution of the two-shears-like mechanism for possible multiple antimagnetic rotational bands in^(103,105)Pd and^(109)Cd nuclei is examined by investigating the orientation of the angular momenta.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 10825522, 10735010 and 10575120)the National Basic Research Program of China (Grant No. 2007CB815001)Chinese Academy of Sciences
文摘Theoretical calculations have been performed for the ν9/2+[624](i13/2) and ν7/2-[503](f7/2) bands of 185Pt in the framework of particle-rotor model. The band properties of signature splitting and configuration mixing have been analyzed. The level energy and signature splitting before the band crossing can be well interpreted by introducing triaxiality. The positive-parity yrast band is pro posed to be dominated by the ν9/2+[624](i13/2) component, while the negative-parity band shows strong mixing of ν7/2-[503](f7/2) and ν9/2-[505](h9/2) configurations.
基金National Natural Science Foundation of ChinaNuclear Industry Science Foundation
文摘AI=2 staggering in superdefonned nuclei has been investigated by a perturbed particle-rotor model, of which all observed features are reproduced in the calculations. It is pointed out that the C4symmetry in Hamiltonian is not the only cause of AI=2 staggering. This model can be used to make a fit to the experimental data in odd-A superdeformed nuclei.
文摘Energy level statistics of a system consisting of six particles interacting by delta force in a two- model coupled with a deformed core is studied in particle-rotor model. For single- shell and two- shell the exact energies for our statistical analysis are obtained from a full diagonalization of the Hamiltonian, while in two- case the configuration truncation is used. The nearest-neighbor distribution of energy levels and spectral rigidity are studied as the function of spin. The results of single- shell are compared with those in two- case. It is showed that the system becomes more regular when single- space is replaced by two- shell although the basis size of the configuration space is unchanged. The degree of chaoticity of the system, however, changes slightly when configuration space is enlarged by extending single- shell to two- shell .
文摘The chaotic properties for six particles interacting by a monopole pairing force in a two-j shell model coupled with a deformed core are studied in the frame of particle-rotor model. The nearest-neighbor distribution of energy levels and spectral rigidity in the two-j shell are compared with those in the single-j case. The results show that the system is more regular in the two-j model than that in the single-j case.
基金supported by Natural Science Foundation of China (Nos. 10775005, 10405001, 10875002, 10735010, 10975007, 10875157, J0730316)the Chinese Major State Basic Research Development Program (No. 2007CB815002)
文摘High-spin states in 157Yb have been populated in the 144Sm（160, 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.
基金The project supported by National Natural Science Foundation of China
文摘-By using particle-rotor model,the configuration of the superderformed(SD)bands in odd-A Hg nuclei is analysed.It is shown that the electromagnetic transitionproperties of the SD bands can be used to further identify the configuration.
基金The project supported by the National Natural Science Foundation of China.
文摘Identical superdeformed bands in <sup>191</sup>Au and <sup>191</sup>Hg have been investigated byusing particle-rotor model within the framework of the BCS （Bardeen-Cooper-Schrieffer） pairing correlation.The identity in the γ-transition energies in these bandsshows that the properties of specific individual orbitals may be important to understandidentical bands.
基金The project supported by National Natural Science Foundation of China.
文摘Using the particle-rotor model,some features of superdeformed bands builtupon j<sub>15</sub> orbitals have been investigated.An excellent agreement between the caleu-lated and observed transition energies,kinematic and dynamic moments of inertiaof Hg（bl）is obtained.
基金The project supported by National Natural Science Foundation of Chinathe Doctoral Program Foundation of Institution of High Education of China
文摘Superdeformed bands of <sup>193</sup>TI are analyzed by using particle-rotor model inconnection with experimental data,considering the possible occurrence of triaxialshape.It is investigated that γ-transition energies and dynamic moments of inertia de-pend on γ-deformation and energy gap.
基金supported by the National Research Foundation of South Africa under Grant Nos.65268,65581,75248,75357,76632,80977,88646,90741,91446,92791,92792,93531,103478,109134 and 116666the Outstanding Youth Fund of the Natural Science Foundation of Shandong Province(No.ZR2020YQ07)the National Natural Science Foundation of China(Nos.U2167202,12075137,12075138,and 12225504).
文摘Progress in the studies of chirality in atomic nuclei at iThemba LABS is reviewed.New regions of chirality,around mass 80 and 190 have been discovered using the AFRODITE array,specifically in the nuclei^(74)As,^(78,80,82)Br,^(81)Kr,and^(193,194,198)Tl.Many phenomena have been observed,including multiple chiral bands in the same nucleus,the coexistence of octupole correlations and nuclear chirality,and the coexistence of pseudo spin and nuclear chirality.The best example of chiral degeneracy to date was found in ^(194)Tl.The level scheme of ^(106)Ag has been revisited and interpreted in terms of two-and four-quasiparticle bands.Investigations using the particle-rotor model have shown that the fingerprints of chirality in the two-quasiparticle system only can occur in an idealised model description.For systems with a higher number of quasiparticles,the calculations showed that nuclear chirality can persist.
基金Supported by the National Natural Science Foundation of China (12205103,12175071)。
文摘Wobbling motion in a system comprising a triaxial rotor and a single quasiparticle is studied employing the particle-rotor model.The energy spectra,wobbling frequencies,electromagnetic transition probabilities,g-factors,angular momentum components,spin coherent state maps,and static quadrupole moments are investigated.These investigations were conducted with regard to the Fermi surface transitioning from the lowest h_(11/2) orbit to the highest one.As the Fermi surface increases,notable transformations occur in the wobbling mode.Initially,the mode exhibits a transverse revolution around the short axis of the nucleus.However,as the Fermi surface continues to increase,the mode gradually shifts to a longitudinal revolution around the intermediate axis.Eventually,it transitions to a transverse revolution around the long axis.Notably,the stability of the long axis transverse mode diminishes relative to its counterpart along the short axis as the total angular momentum increases atγ=20∘.
基金supported bythe National Basic Research Program of China (Grant No. 2007CB815001)the National Natural Science Foundation of China (Grant Nos. 10825522,10735010 and 10575120)the Chinese Academy of Sciences
文摘High-spin states in 161Er have been studied experimentally via the 150Nd(16O, 5n) reaction at a beam energy of 86 MeV. Three rotational bands built on the 5/2+[642], 3/2-[521], and 11/2-[505] configurations have been extended up to high-spin states, and particularly, the α = -1/2 branch of the ground state 3/2-[521] band has been revised significantly. It is found that signature inversion occurs in the 3/2-[521] band after the band crossing in 161Er. The systematics of the signature inversion associated with the 3/2-[521] configuration in the rare-earth region is discussed. The band properties are analyzed within the framework of a triaxial particle-rotor model, and a triaxial deformation is proposed to the 3/2-[521] band.
基金Project Supported by the National Natural Science Foundation of China and China Nuclear Industry Science Foundation.
文摘Through particle-rotor model, band structure of superdeformed bands in odd-A Hg nuclei is analysed. An overall and excellent agreement between the calculated and observed kinematic and dynamic moments of inertia is obtained. The electromagnetic transition properties of SD bands can be used to identify the configuration with certainty.
基金Supported by National Natural Science Foundation of China (10825522,10805058,10775158)West Light Foundation of the Chinese Academy of Sciences (O803080XBB)+2 种基金National Basic Research Program of China (2007CB815001)Project sponsored by SRF for ROCS, SEM (O803090HGJ)Chinese Academy of Sciences
文摘High-spin levels of ^189Pt have been studied with the in-beam T-spectroscopy method via the ^176Yb（^18O,5n） reaction at the beam energies of 88 and 95 MeV. The previously known ＂vi-1 13/2 band has been confirmed, and its unfavored signature branch extended up to the 31/2^＋ state. Within the framework of the triaxial particle-rotor model, the vi-1 13/2 band is suggested to be associated with the 11/2[615] configuration, and to have triaxial deformation.
基金Supported by the Science and Technology Research Planning Project of Jilin Provincial Department of Education (JJKH20220965KJ)the National Natural Science Foundation of China (12175086, 11775098, U1867210, 11405072)the Fundamental Research Funds for the Central Universities
文摘The positive-parity signature partner bands in^(103,105)Pd and^(109)Cd nuclei are investigated using the classical particle-rotor model.Based on the systematic study of neighbouring nuclei,the signature partner bands of ^(105)Pd are assigned to theπ(g^(-4)_(9/2))■ν(g7/2h^(2)_(11/2))configuration,and this assignment is also supported by the present calculations.Furthermore,the calculated$B(E2)$values of such bands of ^(105)Pd reproduce the experimental values well and exhibit a decrease with increasing angular momentum,suggesting that these two bands may originate from antimagnetic rotation.Similar signature partner bands are also found in the neighboring^(103)Pd and^(109)Cd nuclei.The properties of both bands are in general agreement with the fingerprints of antimagnetic rotation,and thus the signature partner bands of^(103)Pd and^(109)Cd are suggested to be candidates for the multiple antimagnetic rotational bands of ^(105)Pd.In addition,the evolution of the two-shears-like mechanism for possible multiple antimagnetic rotational bands in^(103,105)Pd and^(109)Cd nuclei is examined by investigating the orientation of the angular momenta.
