Reviewing nuclear structure properties of even-even Yb isotopes

The medium-to-heavy mass ytterbium isotopes (₇₀Yb) in the rare–earth mass region are known to be well–deformed nuclei. Spectroscopic information becomes scarcer as the neutron number increases, impeding the understanding of nuclear structure in this mass region, where interesting phenomena, such as shape coexistence, have been predicted. The lack of any experimental information on the structure of the neutron-rich ¹⁷⁸Yb and ¹⁸⁰Yb have greatly motivated this study, which can offer useful information for the collective behavior of neutrons and protons, the evolution of shape and shape coexistence. A test run was performed to investigate the population of excited states and a first measurement of the unknown 2⁺₁ lifetime of ¹⁷⁸Yb by means of a two neutron-transfer reaction ¹⁷⁶Yb(¹⁸O,¹⁶O)¹⁷⁸Yb using the ROSPHERE array at IFIN-HH, Romania. From the theoretical point of view, in this work, the reduced transition probabilities B(E2) and transition quadrupole moments Q have been calculated using the IBM-1 and various other theoretical models, including the recently developed Proxy and Pseudo SU(3) model. Good agreement was found between available adopted data and theoretical predictions for ^164-180Yb isotopes. Key Words: nuclear structure, Ytterbium isotopes, IBM-1, Proxy SU(3), lifetimes. (author)