The structure of 99Ru from (α,3n) reaction

Abstract: The results of in-beam investigations of excited states of 99Ru using the 98Mo(α,3n) reaction are presented. Angular distributions of γ–rays and γ–γ coincidences have been measured. Excited states have been identified up to an energy of E = 5603 keV and spin of Iπ= 31/2−. Mean lifetimes τ have been determined using the DSA method for eleven levels. Aligned angular momenta are discussed and the probable (νh11/2) origin of a backbending at frequency about 0.5 MeV was confirmed. The possible role of (νd5/2) alignment at frequencies above 0.5 MeV was pointed out.