Towards a shell-model description of the low-energy structure of deformed nuclei II. Electromagnetic properties of collective M1 bands

A shell-model theory, called the pseudo SU(3) model, which was proposed previously for giving the structure of low-lying states in heavy deformed nuclei is used to predict the number of 1+ states with strong M1 transitions to ground states for the nuclei /sup 154/Sm, /sup 156//sup --//sup 160/Gd, /sup 164/Dy, /sup 168/Er, /sup 174/Yb of the rare earth region and the actinide species /sup 232/Th, /sup 234//sup --//sup 240/U, /sup 242/Pu. Results are also given for E2 and M3 transition strengths in these nuclei. The measures provide a rigorous test of the theory, which in reality is a many-particle Nilsson scheme, because the real M1, E2, and M3 operators are used in the calculations. It is found that the results for E2 strengths using the real quadrupole operator Q-script differ by less than 5 from those of calculations that use the operator Q which is a generator of the pseudo SU(3) symmetry. This is so even for weak interband transitions. To further test the theory additional experimental information on the 2+/sub γ/ states is necessary. In particular, the 1+ → 2+/sub γ/ decay strengths are needed to differentiate between theories for the structure of the giant M1 states. copyright 1987 Academic Press, Inc