High-Resolution Gamma Spectroscopy in the Decay of Pa231

The decay of $^{231}\mathrm{Pa}$ was reinvestigated by means of Ge(Li) singles and coincidence techniques. Our best spectrometer showed a resolution (full width at half maximum) of 850 eV for the 300-keV $\ensuremath{\gamma}$ rays. 78 $\ensuremath{\gamma}$ rays were attributed to the decay of $^{231}\mathrm{Pa}$. A level scheme for $^{227}\mathrm{Ac}$ was proposed and interpreted in terms of rotation bands. Alternating terms in the $K=\frac{3}{2}$ bands were discussed in connection with Coriolis coupling to $K=\frac{1}{2}$ bands.