New level scheme and shell model description of Rn212

Abstract

Level structures of Rn212 have been studied by in-beam γ-ray spectroscopic methods using the Bi209(Li6,3n)Rn212 reaction at beam energies of 28, 30, and 34 MeV. A number of new nonyrast states based on πh9/24 and πh9/23f7/2 configurations have been identified. A 3(−) collective state is also proposed at 2121 keV, which is most likely formed by mixing the octupole vibration with the 3− member of the πh9/23i13/2 multiplet. The level scheme is compared with large-scale shell model calculations and discussed in terms of excitations of valence protons and without contributions from the Pb208 core. An overall excellent agreement is obtained for states that can be described in this model space.