Eur. Phys. J. A (2011) 47: 5
https://doi.org/10.1140/epja/i2011-11005-8

Letter

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

¹ Department of Physics, University of Western Cape, P/B X17, ZA-7535, Bellville, South Africa
² Department of Physics, University of Zululand, P/B X1001, ZA-3886, Kwa Dlangezwa, South Africa
³ iThemba Laboratory for Accelerator Based Sciences, PO Box 722, ZA-7129, Somerset-West, South Africa
⁴ Faculty of Physics, St. Kliment Ohridski University of Sofia, 1164, Sofia, Bulgaria

Received: 30 July 2010
Revised: 15 November 2010
Accepted: 2 December 2010
Published online: 6 January 2011

Abstract

We have used the (, 2n) and (, 4n) reactions and the AFRODITE -ray spectrometer to make a comprehensive study of the nucleus ¹⁵⁴Gd below . While the first excited 0₂ ⁺ state at 681 keV is usually considered to be the head of a -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 and octupole vibrations, pairing and alignments. The implications of this finding, for understanding the structure of transitional rare-earth nuclei, are discussed.