Level Structure of the Odd-AIsotopes of Samarium

Abstract

The levels of ${\mathrm{Sm}}^{145}$, ${\mathrm{Sm}}^{149}$, ${\mathrm{Sm}}^{151}$, ${\mathrm{Sm}}^{153}$, and ${\mathrm{Sm}}^{155}$ have been studied with 0.1% resolution by the ($d,p$) reaction at 12-MeV incident energy. Levels in ${\mathrm{Sm}}^{147}$ have been observed by ($p,p^{\prime }$) reactions at 12 MeV. A large number of previously unknown levels have been observed at excitation energies up to 4 MeV. Previously known levels from decay spectroscopy have, in general, been verified. It is suggested that spherical and deformed nuclear shapes are in evidence close to the ground state in ${\mathrm{Sm}}^{151}$. This conclusion is based partly on these data, on the spectroscopic structure of the neighboring even-even nuclei ${\mathrm{Sm}}^{150}$ and ${\mathrm{Sm}}^{152}$, and on the observed two-neutron separation energies ($S_{2n}$) of odd-$A$ and even-$A$ Sm isotopes in this transition region. A fragmentation of the ($d,p$) intensities among the increasing number of states is observed as one proceeds from ${\mathrm{Sm}}^{145}$ (single closed shell plus one neutron) to ${\mathrm{Sm}}^{155}$ (strongly deformed), as expected from the Nilsson model. Some of the levels below 2 MeV in ${\mathrm{Sm}}^{145}$ are discussed in terms of shell-model configurations. Levels in ${\mathrm{Sm}}^{147}$ are compared with the ${\left(f_{\frac{7}{2}}\right)}^3$ coupling scheme and with the excited-core model. Using particularly the relative intensities of members of the rotational bands, which strongly characterize the assignments, but also the observed energies for the levels and systematics of other deformed odd-$A$ nuclei, the following Nilsson orbitals and some of their associated rotational states have been assigned in ${\mathrm{Sm}}^{153}$ and ${\mathrm{Sm}}^{155}$: $\frac{3}{2}- \mathrm{}\left(521\right)\mathrm{}$, $\frac{5}{2}- \mathrm{}\left(523\right)\mathrm{}$, ½ - (521) and $\frac{5}{2}+ \mathrm{}\left(642\right)\mathrm{}$. The ($d,p$) spectra indicate that the ground state of ${\mathrm{Sm}}^{153}$ is the

Keywords

• MATHVARIANT
• INLINE
• HTTP
• XMLNS
• WWW.W3.ORG/1998/MATH/MATHML
• MSUP

This publication has 39 references indexed in Scilit:

• Energy Levels ofDy165
  Physical Review B, 1964
• Inelastic Proton Scattering from Nuclei with 28 Neutrons
  Physical Review B, 1964
• Levels inDy164from Deuteron Stripping and Inelastic Proton Scattering Experiments
  Physical Review B, 1964
• Energy Levels inSm148andSm150
  Physical Review B, 1964
• Study of Deformed Odd-ANuclei by the (d, p) Reaction
  Physical Review B, 1963
• On the Eu147 decay scheme
  Nuclear Physics, 1962
• Decay ofPm148,Pm148m, andEu148
  Physical Review B, 1962
• Coulomb excitation with 14–20 MeV α-particles: Double excitations and systematics of vibrational states in the rare earth region
  Nuclear Physics, 1960
• Inelastic scattering from odd-mass rare earths
  Nuclear Physics, 1960
• Broad-Range Magnetic Spectrograph
  Review of Scientific Instruments, 1956

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