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 ½ ↔ -½ transition. The isotropic Knight shift, $K_{\mathrm{iso}}$, is (0.262±0.002)% for scandium and (0.367±0.005)% for yttrium. The axial component of the Knight shift, $K_{\mathrm{ax}}$, is -(0.024±0.002)% for scandium and -(0.026±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, ${\nu }_{\mathrm{Q}}=0.144\mathrm{}\pm 0.002$ Mc/sec, so that the quadrupole coupling, $\frac{e^2\mathrm{Qq}}{h}=2.02\mathrm{}\pm 0.03$ Mc/sec. Analysis of the central transition splitting yields the same value within the experimental uncertainty.