The level structures of ${}^{217}\mathrm{Po}$ and ${}^{213}\mathrm{Pb}$ have been studied following the alpha decay of ${}^{221}\mathrm{Rn}$ and ${}^{217}\mathrm{Po}.$ The ground state band of ${}^{217}\mathrm{Po}$ can be interpreted as arising from the mixed $1/2(-0.1;0.5;-2)+3/2(-0;0.6)$ reflection asymmetric orbital with considerable $i_{11/2}$ shell model character. The $<10\mathrm{}\sec$ half-life of the ${}^{217}\mathrm{Po}$ leads to a hindrance factor $<8\mathrm{}$ for the alpha decay to ${}^{213}\mathrm{Pb}$ and suggests the surprising result that the previously proposed ${}^{213}\mathrm{Pb}$ ground state has the configuration $i_{11/2}.$ This anomaly has been discussed.

• Received 6 March 1997

DOI:https://doi.org/10.1103/PhysRevC.56.2324