Identification of 181Hg and shape coexistence in odd-A Hg isotopes

Abstract

In-beam γ-ray transitions in 181Hg, the lightest odd-A Hg isotope known thus far, have been identified from fragment mass-γ and γ-γ coincidence measurements. Five prolate deformed rotational bands were placed in the level scheme. A decoupled band built on the strongly prolate deformed 12−[521] ground state was observed up to 292−. A 52−[512] configuration is suggested for a pair of strongly coupled bands displaying no signature splitting. The other two bands are also signature partner bands. They are populated with the largest intensity and exhibit splitting. They have been associated with the mixed neutron i132 orbitals and are proposed to decay to an i132 isomeric state associated with an oblate state.