Ground-state rotational band in 181Ta

Abstract

The ground-state rotational band in 181Ta has been observed up to a spin of 212+ 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 (≧ 172+) are retarded relative to the rotational model predictions. A suggestion is made that this retardation may be due to the Coriolis antipairing effect.