Coexistence of symmetric and asymmetric shapes in [sup 145]Ba, [sup 145]La.

Autor: Hamilton, J. H., Zhu, S. J., Jones, E. F., Ramayya, A. V., Hwang, J. K., Gore, P. M., Wang, M. G., Cole, J. D., Collins, W. E., Peker, L. K.
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Zdroj: AIP Conference Proceedings; 2000, Vol. 529 Issue 1, p184, 8p, 4 Diagrams, 3 Graphs
Abstrakt: A new region of stable octupole deformation was predicted to occur with its center around the reinforcing shell gaps for β[sub 3]∼0.15 at Z=56, N=88, and with [sub 56][sup 145]Ba[sub 89] was predicted to be a prime candidate for stable octupole deformation. Evidence for stable octupole deformation was found in [sup 144]Ba, [sup 146]Ce and expanded to include odd-A [sup 143]Ba and other neighboring isotopes but was not observed in [sup 145]Ba. Recently we found evidence for the rotational enhancement of stable octupole deformation in [sup 145,147]La. In a reinvestigation of [sup 145]Ba, two new bands were discovered that are connected by enhanced, intertwined E1 transitions to two different previously known bands in [sup 145]Ba. These new data support the predicted presence of octupole deformation in [sup 145]Ba, which is rotation-enhanced above about spin 19/2. In both [sup 145]La and [sup 145]Ba, the low spin ground bands are built on a symmetric rotor shape and at intermediate spins there are shifts to the yrast bands having asymmetric octupole shape. These are the first examples of this type shape coexistence that was earlier predicted could occur in an odd-A nucleus depending on the single particle orbitals. A new side band with equal and constant dynamic and kinetic moments of inertia equal to the rigid body value, as found in superdeformed bands, was discovered in [sup 145]Ba. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]
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