Proton-magnetic-resonance investigation of the electronic hyperfine coupling inβ-phase palladium hydride

Abstract

Measurements of Zeeman and internal nuclear spin-lattice relaxation rates in palladium hydride arising from the electronic hyperfine coupling (10-60 K) yield a surprisingly large value of $\delta -2\mathrm{}$. Explicitly $\frac{T_{1Ze}}{T_{1Ie}}=2.6\mathrm{}\pm 0.1$ for two samples in the $\beta$ phase: Pd${\mathrm{H}}_{0.65}$ and Pd${\mathrm{H}}_{0.82}$. An experiment designed to measure the amount of indirect scalar interaction $〈{{\mathcal{H}}_s}^2〉$ with respect to the dipolar term $〈{{\mathcal{H}}_d}^2〉$ yields an upper bound of $〈{{\mathcal{H}}_s}^2〉<0.1\mathrm{}〈{{\mathcal{H}}_d}^2〉$. It is concluded that the dominant NMR interaction between protons is the direct dipole-dipole term and that there exists a strong electronic correlation between nearest-neighbor protons.