Excited states in ${}^{180}\mathrm{Ta},$ populated in the ${}^{180}\mathrm{Hf}\mathrm{}(p,n)\mathrm{}$ and $\mathrm{}(d,2n)\mathrm{}$ reactions, were investigated by in-beam $\gamma$-ray and conversion-electron spectroscopy. In addition to the excited two-quasiparticle bands with $K^{\pi }{=0\mathrm{}}^{-}$ and $1^{-}$ known from previous work, we have identified six other low-lying two-quasiparticle bands with $K<~4.$ At intermediate K, 12 previously unkown levels were identified that could, however, not be associated reliably with rotational bands. These levels might be of significance in connection with the as yet unresolved problem of the stellar production mechanism for the $9^{-}$ isomer of ${}^{180}\mathrm{Ta}.$ At higher K we observe only levels known from the previous in-beam $\gamma$-spectroscopic studies with heavier projectiles, but suggest for some levels a different ordering into rotational bands based on band-mixing considerations. We also report a deuteron spectrum measured in the ${}^{181}\mathrm{Ta}{\mathrm{}(p,d)\mathrm{}}^{180}\mathrm{Ta}$ reaction with high resolution and statistics. This spectrum served for configuration assignments and yields an energy of $78\pm 1\hspace{0.5em}\mathrm{keV}$ for the $9^{-}$ isomer in ${}^{180}\mathrm{Ta}.$

• Received 4 July 2001

DOI:https://doi.org/10.1103/PhysRevC.65.014309