Ground-state rotational band in 181Ta

The ground-state rotational band in ¹⁸¹Ta has been observed up to a spin of $\text{21}\text{2}{}^{\mathrm{+}}$ using Coulomb excitation with ⁸⁴Kr ions. The nuclear lifetimes of the band members have been determined from the Doppler-broadened lineshapes of the de-excitation γ-rays, and the angular distributions of the γ-rays have been measured. It is found that the E2 transition rates from higher spin states $\text{(≧}\text{17}\text{2}{}^{\mathrm{+}}\text{)}$ are retarded relative to the rotational model predictions. A suggestion is made that this retardation may be due to the Coriolis antipairing effect.