Evidence for the Importance of Soft DeformationPotentials in Strongly Deformed Nuclei

摘要

Excited states of ~(168)Hfwere populated using the~(124)Sn(~(48)Ti,4n) fusion evaporation reaction at the WNSL of Yale University. The lifetimes of the J~n = 4+,6+,8+,and 10+levels alongthe ground state band of ~(168)Hfwere measured by means of the recoil distance Doppler shift (RDDS)method using the New Yale Plunger Device (NYPD) and the SPEEDY Ge detector array. The newlifetime values are sufficiently precise to clearly prove the increase of quadrupole collectivity as afunction of angular momentum in the deformed nucleus ~(168)Hf.The data agree with the predictionsfrom the geometrical Confined B-Soft (CBS) rotor model that involves centrifugal stretching ina soft potential. Relative and absolute EO transition strengths [p~2(E0)] on the transitional pathbetween X(5) and the Rigid Rotor Limit have been evaluated within the framework of the CBS rotormodel, too. Relative inter-band EO transition strengths decrease with increasing angular momentumfor a given potential stiffness, while for increasing potential stiffness, the absolute EO transitionstrengths decrease with increasing angular momentum and increasing potential stiffness.