In order to obtain more evidence on the systematic behavior of nuclear energy levels in the deformed region, a number of neutron-deficient odd-mass activities were studied with internal conversion electron spectrographs. Some scintillation counter measurements were made. Level schemes are postulated for decays leading to the following odd-neutron nuclei: ${\mathrm{Pm}}^{151}$ → ${\mathrm{Sm}}^{151}$, ${\mathrm{Tb}}^{151}$ → ${\mathrm{Gd}}^{151}$, ${\mathrm{Tb}}^{153}$ → ${\mathrm{Gd}}^{153}$, ${\mathrm{Tb}}^{155}$ → ${\mathrm{Gd}}^{155}$, ${\mathrm{Eu}}^{157}$ → ${\mathrm{Gd}}^{157}$, ${\mathrm{Tm}}^{163}$ → ${\mathrm{Er}}^{163}$, ${\mathrm{Tm}}^{165}$ → ${\mathrm{Er}}^{165}$, ${\mathrm{Ho}}^{167}$ → ${\mathrm{Er}}^{167}$, ${\mathrm{Re}}^{183}$ → ${\mathrm{W}}^{183}$, ${\mathrm{Ir}}^{185}$ → ${\mathrm{Os}}^{185}$, ${\mathrm{Ir}}^{187}$ → ${\mathrm{Os}}^{187}$, and ${\mathrm{Ir}}^{189}$ → ${\mathrm{Os}}^{189}$. As a corollary, data are presented for the odd-proton nuclei populated in the decays of ${\mathrm{Pt}}^{189}$ → ${\mathrm{Ir}}^{189}$ and ${\mathrm{Pt}}^{191}$ → ${\mathrm{Ir}}^{191}$. The proposed states are described using the Mottelson and Nilsson predictions. Some conclusions may be drawn concerning such properties of these orbitals as moments of inertia, $\frac{M1\mathrm{}}{E2\mathrm{}}$ mixing ratios, and positions of the intrinsic excitations. Ratios of gamma-ray transition probabilities from the various states are given. Previously published studies of odd-$A$ nuclei in the region of odd-$N$ numbers 99-107 are incorporated in the energy-level systematics.

• Received 29 June 1962

DOI:https://doi.org/10.1103/PhysRev.128.1186