Yrast structure of the two-proton- and three-neutron-hole nucleus 203Hg from the decay of a 53/2+ isomer

The decay of a new, 53/2{sup +}, isomer at 8281 keV in {sup 203}Hg has been studied by {gamma} coincidence spectroscopy. A half-life of 146(30) ns was measured. In addition, another isomeric, 39/2{sup +}, level with a half-life of 7.8(1.5) ns was observed. Some elements of the Rydstroem shell-model interaction have been adjusted to reproduce level energies in nuclei with two to four holes in the {sup 208}Pb core. With this interaction, the new states in the five-hole nucleus {sup 203}Hg are reproduced with an rms error of 105 keV.