X G Wu

Bio: X G Wu is an academic researcher. The author has contributed to research in topics: Yrast. The author has an hindex of 1, co-authored 1 publications receiving 4 citations.

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

Abstract: 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.

Observation of high-spin oblate band structures in Pm 141

Abstract: The high-spin states of $^{141}\mathrm{Pm}$ have been investigated through the reaction $^{126}\mathrm{Te}$($^{19}\mathrm{F}$,4$n$) at a beam energy of 90 MeV. A previous level scheme has been updated with spins up to 49/2$\ensuremath{\hbar}$. 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 $\ensuremath{\Delta}I=1$ $M1$ transitions inside the bands are suggested as the oblate bands with $\ensuremath{\gamma}$ $~$$\ensuremath{-}{60}^{\ifmmode^\circ\else\textdegree\fi{}}$; three other bands with large signature splitting have been proposed with the oblate-triaxial deformation with $\ensuremath{\gamma}$$~$ $\ensuremath{-}{90}^{\ifmmode^\circ\else\textdegree\fi{}}$. The triaxial $n$-particle-$n$-hole particle rotor model calculations for one of the oblate bands in $^{141}\mathrm{Pm}$ are in good agreement with the experimental data. The other characteristics for these bands have been discussed.

Reinvestigation of the collective band structures in odd-odd 138Pm nucleus

Abstract: The high-spin states in the odd-odd 138Pm nucleus have been reinvestigated via the 124Te(19F, 5n) reaction at the beam energy of 103 MeV. Most of the known transitions and levels are confirmed. A number of bands are revised and one new band has been established. For the yrast πh 11/2⊗νh 11/2 band based on 8+ state, no evidence supporting the occurence of signature inversion is found. The experimental and theoretical B(M1)/B(E2) ratios have been calculated for band (2), which support the πg 7/2[413]5/2+ ⊗ νh 11/2[514]9/2− Nilsson configuration assignment. Four bands with ΔI = 2 transitions are tentatively assigned as doubly decoupled bands. The other three bands are proposed as oblate-triaxial bands. The possible configuration assignments for these bands are also discussed under the calculations of total Routhian surface and particle-rotor model.

Systematics on the low-lying spectra in N = 78 ~ 80 isotones

Abstract: Combining the new spectroscopy results of 144Tb and previous spectroscopy studies of neighboring nuclei, a systematic investigation on the low-lying spectra in N = 78 ~ 80 isotones is performed. Good systematics have been found for the coupling patterns which couple the odd nucleon(s), such as πh11/2, , to the 2+, 4+, 6+ and 3- core excitations. It is found that the relative excitation energies of the states formed by coupling h11/2 proton(s) to the 2+, 4+ core excitations are pushed up, in contrast with those formed by coupling h11/2 neutron hole(s) to the 2+, 4+ core excitations, which are pulled down. According to the systematics, the interpretation that the 17/2+ states observed in 141Sm and 143Gd are the fully aligned member of coupling the odd h11/2 neutron hole to the octupole 3- core excitation, is explored to the isotones 145Dy, 142Eu, and 144Tb.