New Mössbauer Levels in the Rare Earths Following Coulomb Excitation

Abstract

By using Coulomb excitation to populate the excited states of the nuclei, new Mössbauer levels have been observed in ${\mathrm{Gd}}^{160}$, and ${\mathrm{Er}}^{168}$. Mössbauer levels have been observed following Coulomb excitation in ${\mathrm{Gd}}^{155}$, ${\mathrm{Gd}}^{156}$, and ${\mathrm{Gd}}^{158}$. For the even-even isotopes of gadolinium, hyperfine structures are poorly resolved, but under appropriate assumptions relative quadrupole moments can be obtained which agree with the values derived from Coulomb excitation cross-section data. Well-resolved magnetic hyperfine structure was observed in ${\mathrm{Er}}^{168}$, and the magnetic energy splitting of (7.8±0.4)×${10}^{-6\mathrm{}}$ eV was obtained. In the case of ${\mathrm{Dy}}^{164}$ a well-resolved hyperfine structure was observed, but the interpretation of the complex structure was not definite.