The $t_{1/2}$=5.7 min ${}_{}{}^{180}{}_{}{}^{}\mathrm{Lu}$ isotope was produced in the ${}_{}{}^{180}{}_{}{}^{}\mathrm{Hf}$(n,p) reaction and its subsequent β decay back to ${}_{}{}^{180}{}_{}{}^{}\mathrm{Hf}$ was studied with a Ge(Li) spectrometer. A radiochemical technique was used to measure the fractional population of the $I^{\pi }$, K${=(8\mathrm{}}^{\mathrm{-}}$,8) isomer in ${}_{}{}^{180}{}_{}{}^{}\mathrm{Hf}$ to be $f_m$=0.005±0.018? The limit on $f_m$ is shown to be too small to account for the nucleosynthesis of ${}_{}{}^{180}{}_{}{}^{}$${\mathrm{Ta}}^{\mathrm{m}}$ in the r process. The possible existence of a high-spin isomer in ${}_{}{}^{180}{}_{}{}^{}\mathrm{Lu}$ and its astrophysical consequences are discussed.

• Received 5 August 1986

DOI:https://doi.org/10.1103/PhysRevC.34.2248