Theory of the Knight Shift and the Relaxation Time in Lead

A relativistic formulation for the hyperfine interaction in metals developed in an earlier paper for alkali metals using Dirac orthoganalized-plane-wave wave functions is applied to metallic lead. The calculated values of the Knight shift $K_s$, ($T_{1}T$), and the Korringa constant $\frac{{K_s}^2{T}_{1}T}{S[S=\frac{{\left(\frac{{\gamma }_e}{{\gamma }_N}\right)}^2\hslash }{4\pi k_B}]}$, including exchange-enhancement effects are found to be 1.47%, 293×${10}^{-4\mathrm{}}$ deg sec and 1.08, respectively. The experimental values are 1.47%, 253×${10}^{-4\mathrm{}}$ deg sec and 0.928, respectively. Possible sources of correction to the calculated Knight shift and relaxation times are listed and analyzed.