High spin spectroscopy for odd-Z nuclei with A approx 160.

摘要

Experimental routhians, alignments, band crossing frequencies, and the B(M1)/B(E2) ratios of the N = 90 isotones and several light Lu (N = 90--96) isotopes are summarized and discussed in terms of shape changes. This systematic analysis shows a neutron- and proton-number dependent quadrupole and (gamma) deformations for these light rare earth nuclei. The stability of the nuclear deformation with respect to (beta) and (gamma) is also found to be particle-number dependent. Such particle-number dependent shapes can be attributed to the different locations of the proton and neutron Fermi levels in the Nilsson diagrams. Configurations dependent shapes are discussed specially concerning the deformation difference between the proton h(sub 9/2) (1/2)(sup (minus))(541) and the high-K h(sub 11/2) configurations. The observed large neutron band crossing frequencies in the h(sub 9/2) (1/2)(sup (minus))(541) configuration support the predicted large deformation of this configuration, but can be reproduced by the self-consistent cranked shell model calculation. Lifetime measurement for (sup 157)Ho, one of the nuclei that show such a large (h bar)(omega)(sub c) in the (1/2)(sup (minus))(541) band, indicates that deformation difference can only account for 20% of such shift in (h bar)(omega)(sub c). 55 refs., 12 figs.