Theoretical analysis of shape transition and axial asymmetry in even-even Yb isotopes

A systematic study on the structural evolution induced by the change in neutron number as well as by the increase in angular momentum for even-even 160-178Yb isotopes has been made using the triaxial projected shell model (TPSM). A detailed analysis of & gamma;-vibrational bands built on ground state has been presented in addition to the yrast band for these nuclei in the present study. The structural changes arising with the increase in neutron number have been quite extensively explained with the help of some interesting nuclear phenomenon. The characteristics of energy ratio and staggering parameter indicate the shape evolution from & gamma;-soft to rigid rotational nuclei as one moves from 160 to 178Yb. Additionally, the calculated electric quadrupole reduced probabilities B(E2), both in-band and inter-band, and gyro-magnetic factors present a reasonably good agreement with the experimental results.