Coulomb excitation of ²²²Rn

The nature of quadrupole and octupole collectivity in ²²²Rn was investigated by determining the electric-quadrupole ( E 2 ) and octupole ( E 3 ) matrix elements using subbarrier, multistep Coulomb excitation. The radioactive ²²²Rn beam, accelerated to 4.23 MeV/u, was provided by the HIE-ISOLDE facility at CERN. Data were collected in the Miniball γ -ray spectrometer following the bombardment of two targets, ¹²⁰Sn and ⁶⁰Ni . Transition E 2 matrix elements within the ground-state and octupole bands were measured up to 10 ℏ and the results were consistent with a constant intrinsic electric-quadrupole moment, 518 ( 11 ) e fm² . The values of the intrinsic electric-octupole moment for the 0 ⁺ → 3 ⁻ and 2 ⁺ → 5 ⁻ transitions were found to be respectively 2360 ^{+ 300} _{− 210} e fm 3 and 2300 ^{+ 300} _{− 500} e fm 3 while a smaller value, 1200 ^{+ 500} _{− 900} e fm ³ , was found for the 2 ⁺ → 1 ⁻ transition. In addition, four excited non-yrast states were identified in this work via γ − γ coincidences.