Observation of Octupole Structures in Radon and Radium Isotopes and Their Contrasting Behavior at High Spin

Abstract

Multinucleon transfer reactions have been used, for the first time, to populate high-spin bands of alternating parity states in ${}^{218,220,222}\mathrm{Rn}$ and ${}^{222,224,226}\mathrm{Ra}$. The behavior of the angular momentum alignment with rotational frequency for the Rn isotopes is very different when compared with Ra and Th isotopes with $N\ensuremath{\approx}134$, indicating a transition from octupole vibrational to stable octupole deformation. Throughout the measured spin range the values of $|{D}_{0}/{Q}_{0}|$ remain constant for ${}^{222}\mathrm{Ra}$ and ${}^{226}\mathrm{Ra}$ and have a very small value for ${}^{224}\mathrm{Ra}$, suggesting that the charge and mass distributions are not affected appreciably by rotations.