Microscopic study of low-lying energy levels and electromagnetic properties in even-even $^{168-178}$Yb nuclei

Abstract

Employing methods based on symmetries for the theoretical description of rare-earth nuclei offers many advantages. Among these, the pseudo-SU(3) shell model has proved to be a very useful method to describe characteristics of these systems and to understand various properties. A theoretical description of the low-lying energy spectrum and electromagnetic properties of isotopes $^{168-178}$Yb is carried out for the first time with this model, comparing theoretical results with the experimental values, where possible. The Hamiltonian includes the $Q \cdot Q$ term which preserves the symmetry, as well as the breaking symmetry of Nilsson and pairing terms. Additionally, three rotor type terms are included that allow us to make a subtle adjustment of the spectrum. The results show that the energy spectrum, the B(E2) transitions, the g-factors and the electric quadrupole moments can be described adequately with the model. Although the model is a powerful tool in the description of low-lying properties of normal parity in heavy deformed nuclei, it finds its strongest limitation in the abnormal parity sector, which has been left out of the description.