Particle-hole induced intruder bands in117Sb and119Sb

Collective structures have been investigated via $\gamma$-ray studies in ${}^{117,119}$Sb. Previously observed strongly coupled $\left(\pi g_{9/2}\right)$ ${}^{-1}$ bands in both nuclei involving 1p-1h proton excitations across the $Z=50\mathrm{}$ gap have been extended, and an alignment of $h_{11/2}$ neutrons identified. New negative-parity strongly coupled bands based on this proton configuration have also been observed in both nuclei. Decoupled bands involving 2p-2h excitations across the gap have been observed in ${}^{119}$Sb, similar to those presented earlier for ${}^{117}$Sb. These bands are interpreted as due to the coupling of a low-$K$ valence proton to the $(\pi g_{7/2}{d}_{5/2}{)}^2\otimes (\pi g_{9/2}{)}^{-2}$ deformed state of the respective ${}_{50}$Sn core nuclei. Anomalies in the expected $h_{11/2}$ neutron crossing of these bands are discussed.