NMR Measurement of Hydrogen Diffusion inβ-Palladium Hydride

Abstract

The pulsed-field-gradient spin-echo method has been applied to measure the self-diffusion coefficient, $D$, for hydrogen in $\beta$-Pd${\mathrm{H}}_{0.70}$. For $296 \mathrm{K}<T<\mathrm{}413\mathrm{} \mathrm{K}$, $D=9.0\mathrm{}\times {10}^{-4\mathrm{}}\times \exp [-\frac{(0.228\mathrm{}\pm 0.006 \mathrm{eV})}{k_{\mathrm{B}}T}]$ ${\mathrm{cm}}^2$/sec with an uncertainty in $D$ of ±8% at 413 K. These results, together with proton spin-lattice relaxation-time measurements in the same specimen, are consistent with diffusion by a random walk on octahedral interstitial sites.