Properties of nuclear states in ¹⁸²₇₅Re populated in the decay of ¹⁸²₇₆Os (22 h)

Abstract

Information about the excited states of the doubly odd nucleide ¹⁸²₇₅Re has been deduced from studies of the radioactive precursor, ¹⁸²₇₆Os (22 h). The γ-ray spectra were measured with several Ge(Li) detectors; the internal-conversion-electron groups were studied with Si(Li) and magnetic spectrometers. Delayed as well as prompt γ-γ coincidence experiments were performed. Fifty-seven transitions are reported in the energy region below 800 keV; 41 of these are assigned between 14 excited states (not including the ground state). The energies of the excited states are determined by making a least-squares fit to the γ-rays assigned between the various pairs of levels. Spin and parity assignments are proposed for most of the levels. An interpretation of some of the states is presented in terms of the Nilsson model and the Gallagher-Moszkowski coupling rules. The half-life of the level at 235.77 keV was measured to be 570±30 ns (in agreement with the value reported by Akhmadzhanov et al.). Reasons are presented for interpreting this level as the (p[402]↑-n[521]↓), I^π = 2⁻ configuration; decay to the ground-state band is thus threefold Ω-forbidden. The influence of this forbiddenness on transition probabilities is discussed.