Knight Shift Anisotropy in Scandium and Yttrium and Nuclear Quadrupole Coupling in Scandium

Abstract

The anisotropic Knight shift of the ${\mathrm{Sc}}^{45}$ and ${\mathrm{Y}}^{89}$ nuclear magnetic resonances (nmr) in polycrystalline scandium and yttrium metal, respectively, has been observed and measured at room temperature by means of the magnetic field dependence of the \textonehalf{} \ensuremath{\leftrightarrow} -\textonehalf{} transition. The isotropic Knight shift, ${K}_{\mathrm{iso}}$, is (0.262\ifmmode\pm\else\textpm\fi{}0.002)% for scandium and (0.367\ifmmode\pm\else\textpm\fi{}0.005)% for yttrium. The axial component of the Knight shift, ${K}_{\mathrm{ax}}$, is -(0.024\ifmmode\pm\else\textpm\fi{}0.002)% for scandium and -(0.026\ifmmode\pm\else\textpm\fi{}0.002)% for yttrium. The scandium nmr spectrum contains a central transition and three pairs of satellite lines, consistent with the $I=\frac{7}{2}$ spin of ${\mathrm{Sc}}^{45}$. The average spacing of the three pairs of satellites yields a lowest pure quadrupole frequency, ${\ensuremath{\nu}}_{\mathrm{Q}}=0.144\ifmmode\pm\else\textpm\fi{}0.002$ Mc/sec, so that the quadrupole coupling, $\frac{{e}^{2}\mathrm{Qq}}{h}=2.02\ifmmode\pm\else\textpm\fi{}0.03$ Mc/sec. Analysis of the central transition splitting yields the same value within the experimental uncertainty.