Nuclear structure in95,97Ru nuclei

The high-spin level structures of the nuclei ${}_{}{}^{95}{}_{}{}^{}$,97Ru have been studied via the ${}_{}{}^{92}{}_{}{}^{}\mathrm{Mo}$ ${(}^6$Li,p2n${)}^{95}$Ru and ${}_{}{}^{93}{}_{}{}^{}\mathrm{Nb}$ ${(}^7$Li,3n${)}^{97}$Ru reactions, using γ-γ coincidence, γ-W(θ), and pulsed-beam-γ measurements. Shell-model calculations of energy levels and B(E2) values for ${}_{}{}^{95}{}_{}{}^{}\mathrm{Ru}$ have been performed and compared with the experimentally observed levels and the measured ${\mathrm{}(21/2)\mathrm{}}^{+}$ and ${\mathrm{}(17/2)\mathrm{}}^{+}$ lifetimes. A collective ΔJ=2 band has been identified with the 1$h_{11/2}$ neutron state in ${}_{}{}^{97}{}_{}{}^{}\mathrm{Ru}$, and discussed in the context of the general nature of collectivity in nuclei outside the N=50 closed shell. No ΔJ=1 band associated with the 1$g_{9/2}$ neutron-hole intruder state was found in either of the N=51,53 Ru nuclei, as observed previously for the 1$g_{9/2}$ proton-hole intruder states in the Z=51 Sb and Z=53 I nuclei.