Deformation properties of osmium, platinum, mercury isotopes from self-consistent calculations

The deformation properties of several isotopes of the elements Os, Pt and Hg have been computed by means of Hartree-Fock plus BCS calculations. The Hartree-Fock potential has been derived from the Skyrme interaction SIII. Two approximations have been used for the treatment of pairing correlations: the constant (versus deformation) gap method and the constant (versus deformation) pairing matrix element method. A good agreement with experimental data is obtained for ground state deformation properties except for the exact location of the prolate-oblate transition as a function of the neutron number. For one nucleus 184Hg, the pairing matrix elements have been calculated from the Gogny interaction D1, in order to study their single-particle state - and deformation - dependence. From these results, the validity of the two approximations used for pairing correlations is discussed. (orig.)