Cranked Hartree-Fock approaches to superdeformation
- Centre d`Etudes de Saclay (France)
Study of superdeformed (SD) rotational bands in the Hg-Pb mass region has been undertaken within the microscopic Hartree-Fock (HF) theory. In this approach, the basic ingredient is an effective nucleon nucleon interaction, which is the only input of the model. The large deformation is set in by a quadrupole constraining operator whose strength is increased until the nucleus reaches a superdeformed equilibrium shape. An overview of this {open_quotes} isthmus{close_quotes} of shape isomerism os superdeformation at zero angular momentum will be presented. Rotational bands are then constructed by means of the usual cranking operator. Without pairing, the ground SD band of {sup 192}Hg has been calculated and identical, or twinned bands, have been obtained in both {sup 194}Hg and {sup 194}Pb. The deexcitation {gamma}-ray energies between these bands differ by at most 2 keV over a range of angular momentum similar to the experimental one. In this calculation, the predicted moment of inertia is only slowly varying with the rotation and does not reproduce the much larger variation observed experimentally. To correct for this behaviour, one has to include pairing correlations. However, it is known that in the simple BCS approximation, the decrease of these correlations is much too fast when the angular momentum is cranked up. To include them in a realistic manner, the HF mean field has been corrected by the Lipkin-Nogami prescription. This amounts to an approximate variation after projection onto the correct nucleon number. Preliminary results show that pairing correlations are still present at spins larger than 40{h_bar} for the SD band of {sup 194}Pb. The full calculation of the identical bands obtained with pairing correlations in this mass region is under progress.
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 386916
- Report Number(s):
- CONF-931044--; CNN: Grant PHY90-13248
- Journal Information:
- Bulletin of the American Physical Society, Journal Name: Bulletin of the American Physical Society Journal Issue: 9 Vol. 38; ISSN 0003-0503; ISSN BAPSA6
- Country of Publication:
- United States
- Language:
- English
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