Search

Theπh9/2[541 1/2−] band in 167Tm has been studied through the 124Sn(48Ca, p4n)167Tm reaction at Ebeam= 210 MeV. The favoured signature of the πh9/2[541 1/2−] band is observed to spin 61/2h̅. A remarkable small gain in aligned angular momentum at the AB-band crossing has been found. The crossing frequency and the gain in aligned angular momentum for 167Tm are compared with data for the N= 98 isotones of Lu, Ta and Re, and contrasted with Cranked Shell Model predictions, based on frequency diabatic configurations. Large deviations are found for the gain in aligned angular momentum.

Calculations of shape-isomeric states in neutron deficient lead isotopes have been performed using the configuration-constrained shell correction method with a Woods-Saxon average potential and a monopole pairing interaction. This approach enables us to decompose the ground state potential energy surface in separate parts characterized uniquely by the number of occupied intruder orbitals. The calculations reproduce the positions of the excited 0+ intruder states. The isotope196Pb is discussed in detail.

Projection of angular momentum on cranking model wave functions is performed for some simple cases. An extensive analysis has been possible since an algebraic projection technique is employed and a detailed numerical example is presented. The distribution of angular momentum as a function of rotational frequency and signature is analysed, and special attention is focused on the fact that the signature does not give any strict selection of angular momenta contained in the cranking wave function.

The level scheme of123Ba has been extended. Bands based on the [523]7/2- and [402]5/2+ Nilsson configurations were established to spins 59/2 (67/2 tentatively) and 29/2, respectively. The first backbend in this region is found to be caused by the alignment of a pair of h11/2 protons. For the first time in this mass region there is evidence for a second crossing due to the alignment of an h11/2 neutron pair in a neutron h11/2 band. The experimental results are compared with self-consistent cranking calculations. A previous suggestion that large ?-deformation is needed to explain the observed bandheads is not supported.

Recent cranked shell model calculations give a possible explanation for the occurrence of two S-bands in Ba-nuclei.