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New insights into the nuclear structure in neutron-rich 112,114,115,116,117,118Pd

Authors :
A. V. Ramayya
W. C. Ma
S. H. Liu
Yue Shi
J. D. Cole
N. J. Stone
I. Y. Lee
J. K. Hwang
N. T. Brewer
Raul Donangelo
Yu. Ts. Oganessian
Y. X. Luo
M. A. Stoyer
A. V. Daniel
G. M. Ter-Akopian
E. H. Wang
S. J. Zhu
John O. Rasmussen
J. H. Hamilton
S. Frauendorf
Furong Xu
Source :
Nuclear Physics A. 919:67-98
Publication Year :
2013
Publisher :
Elsevier BV, 2013.

Abstract

New level schemes of 112,114,115,116,117,118Pd are established by means of γ – γ – γ , γ – γ – γ – γ and γ – γ ( θ ) measurements of prompt fission γ rays from 252Cf using the Gammasphere multi-detector array. Spins/parities were assigned to levels based on γ – γ angular correlation measurements, level systematics and decay patterns. In the even-N isotopes 112,114,116Pd, two sets of odd-parity bands were identified and extended with spins measured in each band. The odd-parity bands with large level staggerings were interpreted as disturbed chirality with less pronounced triaxial deformations in the Pd isotopes than observed in the chiral symmetry breaking 110,112Ru with maximum triaxiality. Onset of wobbling motion was identified from the sign of the signature splitting in the γ band of even–even 114Pd, and probably also in 116Pd, as first seen in the N = 68 isotone 112Ru. Maximal triaxiality in Ru and Pd isotopes is found to be reached for N = 68 , 112Ru and 114Pd, 4 neutrons more than predicted in the theoretical calculations. The new data and TRS calculations allowed a systematic study of the band crossings in the even-N 112,114,116Pd and odd-N 115,117Pd isotopes. Now we find a new overall, more complex shape evolution than previously proposed from triaxial prolate in 110Pd via triaxial oblate in 112Pd to nearly oblate in 114,116Pd with a large change of the triaxial deformation parameter γ toward nearly oblate in the ( π g 9 / 2 ) 2 alignment in 114,115,116,117,118Pd, and triaxial-prolate–triaxial-oblate shape coexisting bands in 115Pd.

Details

ISSN :
03759474
Volume :
919
Database :
OpenAIRE
Journal :
Nuclear Physics A
Accession number :
edsair.doi...........cab118fdd8b71e2e75ef77f28838ac33