Recoil-distance lifetime measurements in 9 6 , 9 7 , 9 8 Ru : Search for possible onset of collectivity at N >~ 52

摘要: Lifetimes of high-spin states in the $N=52\ensuremath{-}54 \mathrm{Ru}$ nuclei have been investigated via ${}^{65}\mathrm{Cu}{(}^{36}\mathrm{S}{,pyn)}^{96,97,98}\mathrm{Ru} (y=4,3,2)$ reactions using recoil-distance Doppler-shift technique. The data were collected coincidence mode. extracted for both positive- and negative-parity ${}^{96}\mathrm{Ru}$ ${}^{98}\mathrm{Ru}$ positive-parity ${}^{97}\mathrm{Ru}.$ levels studied lifetimes range 2--31 ps. observed reduced transition probabilities $B(E2)$ $B(M1)$ are compared with predictions shell model. Theoretical implications these results discussed.