LEVELS IN 185W FROM DECAY OF 185MW AND 185TA

Radiations from the decay of 1.6 min 185mW and 49 min 185Ta have been studied with Ge(Li), Si(Li) and Si surface barrier detectors. Decay schemes of 185mW and 185Ta are proposed. The conversion coefficients and multipolarity assignments for the transitions between the low-lying excited states of 185W were obtained. All the transitions are placed in the level scheme of 185W consisting of the intrinsic states of 3 2- (512) at 0 keV, 1 2-(510) at 23.6 keV, 11 2+(615) at 197.5 keV and 7 2-(503) at 243.7 keV, and their rotational members. The half-life of the 243.7 keV level in 185W has been measured as 19.3±0.5 ns. The absolute gamma-ray transition probabilities are compared with the Weisskopf estimate. The absolute gamma transition 3robabilities for the E2 transitions from the 7 2-(503) level to the 3 2-(512) band, are further compared with theoretical half-lives calculated from the Nilsson and the Faessler-Sheline wave functions. An attempt is made to give a qualitative explanation of the observed branching ratios by including the effect of the Coriolis band mixing. © 1969.