Coulomb excitation paths of high-K isomer bands in 178Hf -: art. no. 242501

Three distinctly different mechanisms are shown to populate the K-pi=6(+) (t(1/2)=77 ns), 16(+) (31 yr), and 8(-) (4 s) isomer bands of Hf-178 by Coulomb excitation. High spin states of the three isomer bands were populated by Coulomb excitation of a hafnium target with a 650 MeV Xe-136 beam. Although direct population of high-K bands is highly K-forbidden, isomer bands in Hf-178 were populated up to spins 13(K=6)(+), 20(K=16)(+), and 14(K=8)(-) with in-band gamma yields of similar to10(-4) of the ground state band. The data are consistent with a rapid increase in K mixing with increasing spin in the isomer bands.