H. B. Ding

High-spin states and collective band structures in the odd–odd 140Pm nucleus

The high-spin states of 140Pm have been investigated through the reaction 126Te(19F, 5n) at a beam energy of 90 MeV. A previous level scheme based on the 8− isomer has been updated with spin up to 23 . A total of 22 new levels and 41 new transitions were identified. Six collective bands were observed. Five of them were expanded or re-constructed, and one of them was newly identified. The systematic signature splitting and inversion of the yrast πh11/2⊗νh11/2 band in Pr and Pm odd–odd isotopes has been discussed. Based on the systematic comparison, two ΔI = 2 bands were proposed as double-decoupled bands; other two bands with strong ΔI = 1 M1 transitions inside the bands were suggested as oblate bands with γ ~ −60°; another band with large signature splitting has been proposed with oblate-triaxial deformation with γ ~ −90°. The characteristics for these bands have been discussed.

Evolution of the X(5) critical-point symmetry in rotating \mathrm{\mathbf {^{176}Os}}

Lifetimes of excited states above 10+ in the yrast band in 176Os have been measured using the Doppler shift attenuation method, via the fusion evaporation reaction . Lifetimes of states over 12+ were measured for the first time. The deduced transitional quadruple moments (Qt), together with the previous data using a recoil distance method, are compared with theoretical calculations based on the X(5) model and the interaction boson model. For the states below spin 10+, the data of previous work support an X(5)-like structure, but for the states above 10+, the value of Qt remains almost constant, being the characteristic of a symmetric rotor. The present result suggests that the shape of the nucleus 176Os changes from X(5) critical-point symmetry to an axially deformed rotor with increasing spin.

High-Spin States in141Pm

The high-spin states of 141Pm nucleus have been studied by using in-beam γ-ray spectroscopy technology through the126Te(19F, 4n) reaction at a beam energy of 90 MeV. The previous level scheme has been extended with spin up to 49/2 ℏ. Many new levels and transitions are identified. Five collective band structures are observed. Based on systematic comparison with the neighboring nuclei, two bands with strong ΔI = 1 M1 transitions inside the bands are proposed as the oblate bands with γ~−60°, and three bands with large signature splitting have been suggested as the oblate-triaxial deformation with γ~−90°. The characteristics for these bands have been discussed.

Observation of high-spin oblate band structures in {sup 141}Pm

The high-spin states of {sup 141}Pm have been investigated through the reaction {sup 126}Te({sup 19}F,4n) at a beam energy of 90 MeV. A previous level scheme has been updated with spins up to 49/2({h_bar}/2{pi}). Six collective bands at high spins are newly observed. Based on the systematic comparison, one band is proposed as a decoupled band; two bands with strong {Delta}I=1 M1 transitions inside the bands are suggested as the oblate bands with {gamma} {approx}-60 deg.; three other bands with large signature splitting have been proposed with the oblate-triaxial deformation with {gamma}{approx} -90 deg. The triaxial n-particle-n-hole particle rotor model calculations for one of the oblate bands in {sup 141}Pm are in good agreement with the experimental data. The other characteristics for these bands have been discussed.

Magnetic rotation in {sup 112}In

The high spin states of {sup 112}In have been investigated with in-beam {gamma}-ray spectroscopic methods using the {sup 110}Pd({sup 7}Li,5n){sup 112}In reaction at a beam energy of 50 MeV. A level scheme with three band structures has been established and their configurations are discussed. The positive-parity dipole band has been assigned as a magnetic rotation band. Particle-rotor model calculations have also been performed to interpret the rotational structures in {sup 112}In.

New Band Structures in A∼110 Neutron‐Rich Nuclei

The high spin states of neutron‐rich nuclei in A∼110 region have been carefully investigated by measuring prompt γ‐γ‐γ coincident measurements populated in the spontaneous fission of 252Cf with the Gammasphere detector array. Many new collective bands have been discovered. In this proceeding paper, we introduce some interesting new band structures recently observed by our cooperative groups, that is, the one‐phonon‐ and two‐phonon γ‐vibrational bands in odd‐A 103Nb, 105Mo and 107Tc, the chiral doublet bands in even‐even 106Mo, 110Ru and 112Ru, and the pseudospin partner bands with in 108Tc. The characteristics of these band structures have been discussed.The high spin states of neutron‐rich nuclei in A∼110 region have been carefully investigated by measuring prompt γ‐γ‐γ coincident measurements populated in the spontaneous fission of 252Cf with the Gammasphere detector array. Many new collective bands have been discovered. In this proceeding paper, we introduce some interesting new band structures recently observed by our cooperative groups, that is, the one‐phonon‐ and two‐phonon γ‐vibrational bands in odd‐A 103Nb, 105Mo and 107Tc, the chiral doublet bands in even‐even 106Mo, 110Ru and 112Ru, and the pseudospin partner bands with in 108Tc. The characteristics of these band structures have been discussed.

Collective band structures in neutron-rich {sup 106,107}Tc

The high spin states of neutron-rich {sup 106,107}Tc nuclei have been reinvestigated by observing prompt {gamma} rays from the spontaneous fission of {sup 252}Cf. In {sup 106}Tc, a previously known collective band is expanded, and a new collective band is identified. In {sup 107}Tc, a collective band based on the {pi}5/2{sup -}[303] orbital is confirmed and extended. Inconsistencies in the configuration assignments for positive parity bands in {sup 105,107}Tc in the previous reports are clarified. The spins and parities as well as the configurations for the two bands in {sup 106}Tc are assigned according to the angular momentum alignments and g-factor calculations. Other characteristics for the observed bands are discussed.

New insights into the collective band structures of nuclei with A = 100–112

With our high statistics γ‐γ‐γ data set taken with Gammasphere, we have identified a variety of new phenomena in A = 100–112 nuclei. The one‐ and two‐ phonon γ bands in 104,106Mo have been extended and similar bands identified in 108Mo and for the first time in both an odd N nucleus, 105Mo and an odd Z nucleus, 103Nb. The one‐ and two‐ phonon γ band energy levels in 104,105,106,108Mo are remarkably similar with a trend toward lower energy as N increases. In 108,110,112Ru the one phonon γ bands show a completely different behavior from 104–108Mo with very large odd‐even spin level energy staggering in 112Ru. Our data indicate a maximum triaxiality around 112Ru. In 100Nb which lies between N = 58 and 60 where a sudden shift from spherical to superdeformed structures occurs in Sr and Zr nuclei, we have discovered a Kπ = 1+ deformed ground state band. In 108Tc, we found the first pseudospin partner bands with nearly degenerate energies in this mass region.

Identification of pseudospin partner bands in {sup 108}Tc

High-spin structures in the neutron-rich

High-spin states and collective oblate bands in {sup 139}Nd

^{108}\mathrm{Tc}