The lifetime of the 2(1)(+) state of Po-212 was measured in the Pb-208(C-12, Be-8)Po-212 transfer reaction by gamma-ray spectroscopy employing the recoil distance Doppler shift (RDDS) method. The derived absolute B(E2) value of 2.6(3) W.u. indicates a low collectivity and contradicts previous claims of alpha-cluster components in the structure of the 2(1)(+) state. It is demonstrated that a consistent description of the properties of the 2(1)(+)-4(1)(+)-6(1)(+)-8(1)(+) sequence in Po-212 cannot be achieved in the framework of a single-j shell-model calculation, either. This puzzle is traced to the properties of the seniority-2 configurations in Pb-210 and Po-210.
Kocheva, D., Rainovski, G., Jolie, J., Pietralla, N., Blazhev, A., Altenkirch, R., ... Van Isacker, P. (2017). Low collectivity of the 2(1)(+) state of Po-212
. Physical Review C
(4), . https://doi.org/10.1103/PhysRevC.96.044305