The level structure of ${}^{214}\mathrm{At}$ has been studied using the alpha decay of the ground state and high spin isomer of ${}^{218}\mathrm{Fr}$ and coincident gamma rays. This study was also aided by observing the alpha decay of the ground state and high spin isomer of ${}^{214}\mathrm{At}$ into known levels in ${}^{210}\mathrm{Bi}.$ Four additional levels and minor changes in level energies are observed. Of greater importance is the tentative assignment of a large number of spins and parities. This in turn allows the tentative identification of 9 of the 10 members of the $\pi {(h}_{9/2}{)}^3\nu {(g}_{9/2}{)}^3$ configuration which is also calculated theoretically. A survey of the experimental systematics of the $\pi {(h}_{9/2}{)}^m\nu {(g}_{9/2}{)}^n$ configuration in the odd-odd nuclei from ${}^{210}\mathrm{Bi}$ to ${}^{218}\mathrm{Fr}$ shows quite clearly the compression of the level structures and the increased mixing between the configurations with the addition of nucleons. This is also mirrored in the theoretical calculations.

• Received 23 June 1998

DOI:https://doi.org/10.1103/PhysRevC.59.101