Revised B(E3) transition rate and structure of the 3− level in 96Zr

The B(E3) transition strength from the 1897-keV, 3− level in 96Zr has been reevaluated from six high-statistics, independent data sets. The measured value of 42(3) W.u. is significantly lower than that adopted in recent compilations. It is, however, in line with the global systematics of collective B(E3) rates found throughout the periodic table. Thus, the “exceptional” character of this transition, that challenged theory, no longer applies. Monte Carlo shell-model calculations indicate that the collectivity of the octupole vibration arises from both proton and neutron excitations involving a large number of orbitals. Keywords: 90≤A≤149, 3− level, Octupole excitation, Lifetimes and branching ratios, B(E3) strength, Monte Carlo shell model calculations