Energy Levels ofDy165

Abstract

Eighty levels which have been observed in ${\mathrm{Dy}}^{165}$ utilizing the reaction ${\mathrm{Dy}}^{164}(d, p){\mathrm{Dy}}^{165}$ with 12-MeV deuterons are reported. The ground-state $Q$ for the reaction was determined as 3488±5 keV. Thermal neutron capture gamma rays from a sample of natural dysprosium have been measured over the energy range of 900 to 6000 keV. The neutron binding energy of ${\mathrm{Dy}}^{165}$ is determined to be 5715±4 keV. These complimentary methods are a considerable aid in analysis, because the observed intensities permit spin assignments for (a) those levels populated by the strong high-energy capture gamma rays and (b) several of the ($d, p$)-populated levels. The analysis suggests the following spectroscopic interpretation (band head energies, keV, in parentheses; Nilsson asymptotic quantum numbers in brackets): (ground state), $\frac{7}{2}+\left[633\right]\mathrm{}$ with superimposed rotational to $\frac{13}{2}+$; (108.16), ½-[521] rotational band to $\frac{11}{2}-$; (184), $\frac{5}{2}-\left[512\right]\mathrm{}$ rotational band to $\frac{11}{2}-$; (∼535), $\frac{5}{2}-\left[523\right]\mathrm{}$ rotational band to $\frac{9}{2}-$; (539), $\frac{3}{2}+\gamma$ band built on $\frac{7}{2}+\left[633\right]\mathrm{}$ with rotational members to $\frac{9}{2}+$; (574), $\frac{3}{2}-\gamma$ band on ½-[521] with rotational members to $\frac{7}{2}-$; and (606), $\frac{3}{2}-\left[521\right]\mathrm{}$? rotational band to $\frac{5}{2}-$. The gamma vibrational bands are the first postulated on odd-neutron intrinsic Nilsson orbitals. An analysis is made of the $K-2\mathrm{}$ gamma bands of odd-$A$ nuclei. Their energy systematics is found to mirror closely that of the gamma bands of neighboring even-even nuclei.