Narrow Results

The pseudo-spin concept and the SD-pair shell model provide for tractable truncations of large model spaces. We tested the compatibility of these concepts, and hence the applicability of the SD-pair shell model to its pseudo SD-pair analog, for the (1h_9/2 2f_7/2 2f_5/2 3p_3/2 3p_1/2)⁸ system. The validity of the SD-pair concept is found to survive under pseudo-spin transformation.

The γ-unstable limit of the interacting boson model for identical nucleon systems (IBM-I) was studied within the framework of the SD-pair shell model. The results show that the properties of this limit as realized within the boson picture can be reproduced well within a fermion framework.

The SD-pair shell model (SDPSM) is shown to reproduce approximately typical spectra, E2 transition strengths of the U(5), SO(6), SU(3) and SU*(3) limits of the interacting boson model (IBM). The shape phase transitional patterns of the IBM can also be reproduced in the SDPSM. This analysis confirms that the IBM has a sound shell-model foundation; it also demonstrates that the truncation scheme adopted in the SDPSM is reasonable.