Simple applications of the pairing-plus-quadrupole-plus-octupole model

The octupole-octupole interaction has been added to the old pairing-plus-quadrupole model. Symmetries of the HF mean field are discussed. An overview is presented of the ground-state deformations for a singlej orbital and two opposite-parity,j, j – 3 orbitals. Breaking of various symmetries can be studied within this model. It is shown that the pairing and the quadrupole-quadrupole interaction stabilize the mean field against octupole deformation. For the singlej orbital, except for one particularj value, no non-axial quadrupole deformations were found. For two opposite-parityj, j –3 orbitals, non-axial octupole deformations occur in most cases. Also axial and non-axial quadrupole deformations were found to be induced by octupole deformations.Communicated by: X. Campi