Collective model description of transitional odd-A nuclei. II. Comparison with unique parity states of nuclei in the A=135 and A=190 mass regions
Recent experimental data on unique-parity spectra of odd-$alpha$ nuclei in the A = 135 and A = 190 mass regions are compared in a systematic way with calculated energies and transition probabilities of a quasiparticle coupled to a rotating triaxial core. The comparison yields detailed evidence for triaxial shapes. Complex spectra of strongly coupled structure as well as decoupled structure and various intermediate types are reproduced by the model with core parameters $beta$ and $gamma$ determined from neighboring even nuclei. The coexistence of $delta$I = 1 band structures, seen in some of the experimental spectra, is explained as a consequence of the shape asymmetry. In the A = 190 region, the odd-A spectra confirm the existence of a gradual shape transition from prolate-type shapes ($sup 186$Os, $gamma$ = 16$sup 0$) to oblate-type shapes ($sup 198$Hg, $gamma$ = 37$sup 0$). Energies and lifetimes in A approximately 135 nuclei reveal prolate triaxial shapes with $gamma$-values in the range 20$sup 0$ less than $gamma$ less than 30$sup 0$. Contrary to the expectation of very $gamma$-soft, fluctuating shapes which is based on calculated potentials, the present work seems to indicate that a number of transitional nuclei may have rather stable triaxial shapes. (NL)
- Research Organization:
- California Univ., Berkeley (USA). Lawrence Berkeley Lab.
- NSA Number:
- NSA-33-013746
- OSTI ID:
- 4106471
- Journal Information:
- Nucl. Phys., A, v. 249, no. 1, pp. 141-165, Other Information: Orig. Receipt Date: 30-JUN-76; Bib. Info. Source: NL (Netherlands (sent to DOE from))
- Country of Publication:
- Netherlands
- Language:
- English
Similar Records
New effective interaction for f{sub 5}pg{sub 9}-shell nuclei
Shapes of neutron-rich A{approx_equal}190 odd-odd nuclei
Related Subjects
643501*
*EVEN-ODD NUCLEI- COLLECTIVE MODEL
*ODD-EVEN NUCLEI- COLLECTIVE MODEL
BRANCHING RATIO
ENERGY-LEVEL TRANSITIONS
EXCITED STATES
HEAVY NUCLEI
INTERMEDIATE MASS NUCLEI
LIFETIME
MIXING RATIO
MOMENT OF INERTIA
NUCLEAR DEFORMATION
PARITY
SPIN
YRAST STATES