Congruent band structures in 154Gd : Configuration-dependent pairing, a double vacuum and lack of β -vibrations

This is the authors' abstract. We don't add key points for this paper.

We have used the ( α , 2n) and ( α , 4n) reactions and the AFRODITE γ -ray spectrometer to make a comprehensive study of the nucleus 154Gd below 20 . While the first excited 02 + state at 681 keV is usually considered to be the head of a Kπ=0⁺ β -vibrational band, we propose that the data are best described as two separate vacuum states, the ground state and the 681 keV level, each with its own γ and octupole vibrations, pairing and alignments. The implications of this finding, for understanding the structure of transitional rare-earth nuclei, are discussed.