The level structure of ${}_{}{}^{219}{}_{}{}^{}\mathrm{Ac}$ up to a spin of J=(31/2) and $E_x$=2.2 MeV has been studied via the ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}$${(}^{13}$C,3nγ) reaction. The dominant γ-ray deexcitation sequence consists of two parallel cascades, each containing alternating positive and negative parity states. In addition, there is a sideband probably built on the π$i_{13/2}$ single particle state. The most striking feature of this level scheme is the appearance of parity doublets similar to those seen in the heavier actinides.

• Received 16 January 1985

DOI:https://doi.org/10.1103/PhysRevC.31.1977