New level scheme and shell model description of Rn212

Level structures of Rn-212 have been studied by in-beam gamma-ray spectroscopic methods using the Bi-209(Li-6, 3n)Rn-212 reaction at beam energies of 28, 30, and 34 MeV. A number of new nonyrast states based on pi h(9/2)(4) and pi h(9/2)J(7/2) 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 pi h(9/2)(3)i(13/2) 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 Pb-208 core. An overall excellent agreement is obtained for states that can be described in this model space.