An experimental investigation of the odd-odd ${}^{162}\mathrm{Lu}$ nucleus, following the ${}^{148}\mathrm{Sm}{(}^{19}\mathrm{F},5n)$ reaction at beam energy $E_{\mathrm{lab}}=112\mathrm{}\mathrm{}\mathrm{MeV},$ has been performed through in-beam gamma-ray spectroscopy. It revealed three signature-split bands. The yrast band based on $\pi h_{11/2}\otimes \nu i_{13/2}$ configuration exhibits anomalous signature splitting (the unfavored signature Routhian lying lower than the favored one) whose magnitude $\Delta e^{\prime }\approx 25\mathrm{keV},$ is considerably reduced in contrast to sizable normal signature splitting $\Delta e^{\prime }\approx 125$ and 60 keV observed in the yrast $\pi h_{11/2}$ bands of the neighboring odd-$A$ ${}^{161,163}\mathrm{Lu}$ nuclei, respectively. The signature inversion in this band occurs at spin $\sim 20ħ$ $(\mathrm{f}\mathrm{r}\mathrm{e}\mathrm{q}\mathrm{u}\mathrm{e}\mathrm{n}\mathrm{c}\mathrm{y}=0.37\mathrm{}\mathrm{}\mathrm{MeV}).\mathrm{}$ The second signature-split band, observed above the band crossing associated with the alignment of a pair of $i_{13/2}$ quasineutrons, is a band based on the four-quasiparticle $[\pi h_{11/2}{\mathrm{}\left[523\right]7/2}^{-}\otimes \nu h_{9/2}{\mathrm{}\left[521\right]3/2}^{-}\otimes (\nu i_{13/2}{)}^2],$ i.e., ${\mathrm{EABA}}_p{(B}_p),$ configuration. The third signature-split band is also likely to be a four-quasiparticle band with configuration similar to the second band but involving $F$ quasineutron, i.e., ${\mathrm{FABA}}_p{(B}_p).\mathrm{}$ The experimental results are discussed in comparison with the existing data in the neighboring nuclei and in the framework of the cranking shell model.

• Received 30 January 1997

DOI:https://doi.org/10.1103/PhysRevC.56.1281