Weak K hindrance manifested in α decay of the 178Hfm2 isomer

An experiment has been performed to detect the alpha emission mode in Hf-178(m2) isomer decay and a partial half-life of (2.5 +/- 0.5)x10(10)y was measured. It was concluded that alpha decay is strongly retarded by the centrifugal barrier arising due to the high spin of this isomeric state. Additional analysis shows, however, that the K-hindrance in this alpha decay is relatively weak, despite the strong manifestation of spin-hindrance.