Decay of mass-separated 189mHg (8.7 min) and 189gHg (7.7 min) to 189Au

The decays of 189Hg (8.7 min; Jπ=13/2+) and 189Hg (7.7 min; Jπ=3/2-) have been studied with mass-separated sources from the UNISOR facility. Multiscaled spectra of γ-rays, X-rays, and conversion electrons, as well as γγt, γXt, eγt, and eXt coincidences were obtained. Decay schemes have been constructed incorporating >95% of the decay intensities assigned to the high-spin and low-spin decays. The γ-ray gated conversion-electron spectra permitted the determination of 119 conversion-electron subshell ratios. Portions of the level scheme bear a remarkable resemblance to the heavier and lighter odd-mass Au isotopes. An extensive band of states is observed built upon the h9/2 intruder state at 325 keV. This band is markedly different from the corresponding bands in 187Au and 185Au, indicating a major change in the cores, i.e. between 188Pt and 186,184Pt. Evidence for oblate-hole-prolate-particle symmetry in 189Au is discussed. Completeness of complex decay schemes far from stability is addressed. (orig.)