No abstract

We report on Hartree-Fock-Bogoliubov (HFB) calculations of the ground-state rotational band of the heavy nucleus 254 No recently observed experimentally. The calculated quadrupole deformation is consistent with the experimental value of β = 0.27 and is almost constant over the whole band. We also reproduce fairly well the excitation spectra and moments of inertia of this isotope up to the maximal experimentally observed state of spin 20. The rather high stability of this nucleus against fission is illustrated by the deformation energy curve providing very high fission barriers at zero spin within the HFB and HFB plus Lipkin-Nogami formalisms. The variation of these barriers with increased angular velocities is also studied. PACS.

The present paper aims at proving that the collective effects of pairing correlations in rotating nuclei can be embodied by a simple S-type couplingà la Chandrasekhar between rotational and intrinsic vortical collective modes. The demonstration is performed on the basis of a comparison between the solutions of microscopic calculations within the HFB and the HF Routhian formalisms. The HF Routhian solutions are constrained to have the same Kelvin circulation expectation value as the HFB ones. It is shown in several mass regions, pairing regimes, and for various spin values that this procedure yields moments of inertia, angular velocities, and current distributions which are very similar within both formalisms. We finally present perspectives for further studies.