Prediction of octupole-deformation effects in superdeformed nuclei of A∼150 and A∼190 mass regions and possible interrelation with pseudo-spin symmetry

Abstract

Stability with respect to axially symmetric but mirror-asymmetric distortions in superdeformed nuclei is analysed. Calculations based on the deformed Woods-Saxon potential and the cranking method together with the generalised Strutinsky approach indicate the existence of octupole-shape driving shell effects persisting up to the very high spin limit in superdeformed nuclei of both A∼150 and A∼190 mass regions. The strongest effects are predicted for Z∼62−68(combined with N∼82−88) and for N∼110–118 (combined with Z∼ 80) particle numbers at quadrupole deformation β 2∼0.60 and β 2∼0.45, respectively. In both mass ranges the low lying octupole vibrations rather than the static octupole shapes are to be expected in most of the cases. The physical consequences of the above theoretical predictions are discussed in the context of the rotational bands based on the octupole oscillations and the symmetry properties of the decoupling parameter in the K= 1 2 bands.