NEW STUDIES ON THE ASPECTS OF NUCLEAR SHAPES.

Using the pairing-deformation-frequency self-consistent total-Routhian-surface and configuration-constrained potential-energy-surface calculations, we have studied nuclear deformation and its effect on the structure of nuclei. It was found that the high-order multipolarity-six (β6) deformation plays a significant role in superheavy nuclei. Possible non-collective high-spin isomeric states which locate in the second well of actinide nuclei have been investigated with the predictions of excitation energies and configurations. High-spin isomers can extend shape coexistence in A ~190 neutrondeficient nuclei. Triaxiality with γ~30° is found in the ground and excited rotational states of the A ~ 70 germanium isotopes. Octupole correlations have also been discussed in different mass regions. In recent experiments, the textbook nucleus 158Er has been reached at ultrahigh spins around 65ħ . We have studied 158Er ultrahigh-spin states by means of the self-consistent tilted-axis-cranking method based on the Nilsson shell correction and the Skyrme-Hartree-Fock model. The calculation with a γ ≈ 12° triaxial-strongly-deformed (TSD) excited configuration can well reproduce the observed large transitional quadrupole moment. It is demonstrated that the TSD minimum at negative γ deformation which appears in the principal-axis-cranking approach is a saddle point if allowing the rotational axis to change direction. [ABSTRACT FROM AUTHOR]