An on-line isotope-separator facility has been used to determine the energies and intensities of sixteen γ rays following the ${\beta }^{\mathrm{-}}$ decay of the recently discovered isotope ${}_{}{}^{159}{}_{}{}^{}\mathrm{Sm}$. From these data, the existence of a new level in ${}_{}{}^{159}{}_{}{}^{}\mathrm{Eu}$ at 1051.80 keV has been established, and tentatively assigned as the ${(7/2\mathrm{}}^{\mathrm{-}}$[523] bandhead. The ${}_{}{}^{159}{}_{}{}^{}\mathrm{Sm}$ ground state is tentatively assigned as the ${(5/2\mathrm{}}^{\mathrm{-}}$[523] Nilsson state. Some of the deduced features of the reduced γ-ray transition probabilities as they relate to the proposed rotational-band structure in ${}_{}{}^{159}{}_{}{}^{}\mathrm{Eu}$ are briefly discussed.

• Received 23 March 1987

DOI:https://doi.org/10.1103/PhysRevC.36.1540