Hyperfine Structure of the Spectra of Nd and Gd

Study of the hyperfine structure of the spectrum of Nd ii with separated isotopes yielded the result that the nuclear magnetic moments of the odd isotopes are $\mu \left({\mathrm{Nd}}^{143}\right)=-1.1\mathrm{}\pm 0.1$ nm and $\mu \left({\mathrm{Nd}}^{145}\right)=-0.69\mathrm{}\pm 0.10$ nm. The isotope shift in Nd i $\lambda 4924$ was measured and the ratio of the distances of the neighboring isotopes was found to be $\Delta \nu \mathrm{}(142-143):\Delta \nu \mathrm{}(143-144):\Delta \nu \mathrm{}(144-145):\Delta \nu \mathrm{}(145-146):\Delta \nu \mathrm{}(146-148):\Delta \nu \mathrm{}(148-150)={0.4}_0:{0.5}_7:{0.2}_0:{0.7}_3:1:1.5\mathrm{}$. From the hyperfine structure of the spectrum of Gd i the nuclear spins of the odd isotopes ${\mathrm{Gd}}^{155}$ and ${\mathrm{Gd}}^{157}$ were found to be equal to or larger than $\frac{5}{2}$, the magnetic moments being negative. Under the assumption that the spins are equal to the values predicted by the nuclear shell structure theory, namely $\frac{7}{2}$, the magnetic moments were calculated to be $\mu \left({\mathrm{Gd}}^{155}\right)=-0.19\mathrm{}\pm 0.05$ nm and $\mu \left({\mathrm{Gd}}^{157}\right)=-0.33\mathrm{}\pm 0.06$ nm. An anomalous isotope shift of the even isotopes of Gd was found: $\Delta \nu \mathrm{}(160-158):\Delta \nu \mathrm{}(158-156):\Delta \nu \mathrm{}(156-154):\Delta \nu \mathrm{}(154-152)=1:0.97\mathrm{}\pm 0.02:1.21\pm 0.05:2.2\pm 0.1$.