An 8 − isomeric state in the 106-neutron nuclei: 180W, 182Os and 184Pt

Abstract

The decay of a two-neutron, 8 −, isomeric state has been observed in three nuclei having 106 neutrons. The half-lives of these isomers are in the region of 1 msec. In each of the isotones 180mW, 184mOs and 184mPt, there were observed five prominent transitions. Four of these are the E2 transitions of the 8 → 6 → 4 → 2 → 0 cascade in the ground-state band. The fifth transition is a very hindered E1 that de-excites an 8 −, 8 isomeric level and populates the 8 +, 0 level of the ground-state band. Despite the appreciable difference between the properties of these nuclei, as can be seen by comparing the well-developed rotational spectrum of 180W with that of the poor rotor 184Pt, the isomeric transitions seem to exhibit a striking similarity. In 184mPt, the isomeric decay also populates other levels. Among them were tentatively identified two members of the β-Vibrational band. Their position relative to the ground-state band in this transitional-region nucleus is of special interest.