Shape isomerism and spectroscopy of 177Hg
Melerangi A., Appelbe D., Page RD., Boardman HJ., Greenlees PT., Jones P., Joss DT., Julin R., Juutinen S., Kettunen H., Kuusiniemi P., Leino M., Muikku MH., Nieminen P., Pakarinen J., Rahkila P., Simpson J.
High spin states in the 177Hg nucleus were populated by the 144Sm(36Ar,3n)177Hg reaction at a beam energy of 178 MeV. The emitted prompt γ rays were detected with the Jurosphere γ-ray spectrometer, while the recoiling nuclei were identified using an active stopper at the focal plane of the gas-filled separator RITU. A quasi-rotational band that decays to an isomeric state with a half-life t 1/2=1.50±0.15 μs and its subsequent γ decay to the ground state of 177Hg have been observed for the first time. Based on the observed decays from this isomeric state, we suggest that the spin of the ground state of 177Hg is Jπ=7/2-. In addition, a sequence of transitions that bypass this isomeric state has also been observed. Evidence for shape coexistence is presented. The properties of the observed states are discussed in terms of the systematics of the mercury nuclei in this transitional region.