The band structure of ${}^{219}\mathrm{Ra}$ has been studied via the ${}^{208}\mathrm{Pb}{(}^{14}\mathrm{C},3n)$ reaction using both $\gamma -\gamma$ and conversion electron-$\gamma$ coincidence measurements. This nucleus is at the lower mass limit of a region where static octupole deformation may occur. The conversion coefficients of seven transitions and two upper limits on conversion coefficients have been determined for the first time. The results establish the alternating parity nature of a sideband in this nucleus and also resolve an apparent conflict between radioactive decay data and heavy-ion reaction data. The resulting level scheme of ${}^{219}\mathrm{Ra}$ can be explained either by intermediate coupling of the odd neutron to a reflection symmetric core and a low frequency octupole vibrational mode or by strong coupling to a statically octupole deformed core.

• Received 15 December 1999

DOI:https://doi.org/10.1103/PhysRevC.62.021301