Hybridized bands and parity splitting in the odd-odd nucleus220Ac

The high spin state structure of the nucleus220Ac was investigated by means of the209Bi(14C, 3n) reaction. In beamγ ray spectroscopy was carried out using the Château de Cristal multidetector array. Gamma ray multipolarities were established by extracting directional correlation ratios from the Ge—Ge coincidence data and by intensity balance considerations. The level scheme, established up to 18 ħ above the lowest observed state, consists of three alternating parity bands. The data are interpreted in terms of the reflection asymmetric shapes of the nucleus. The analysis of the parity doublet candidates does not show the decrease of the parity splitting predicted for an odd-odd nucleus.