174Hf and 174Yb by the Projected Shell Model with Improved 4-quasiparticle basis

The rare-earth nuclei 174Hf and 174Yb are studied in the framework of the projected shell model. The calculations are carried out with an improved version of code which contains all types of four-quasiparticle basis in the configuration space. Both the yrast band and the multi-quasiparticle excited bands can be well reproduced. Compared with the experimental data, our calculations improve the previous results, especially for high spin states. This improvement suggests that the newly added configurations are important. In 174Yb, a new possible configuration is suggested for the observed Kπ = 14+ band, and the decay of the Kπ = 6+ isomeric state to the yrast band is discussed. (nuclear physics)