Solid-state proton nuclear magnetic resonance studies of hydrogen site occupancies, electronic structure properties, and diffusion behavior in transition-metal hydrides

Solid-state NMR techniques have been used to measure the proton lineshapes, Knight shifts, and relaxation times in several transition metal hydrides. The objective is to obtain a better understanding of the roles of host metal structures and substitutional alloying on the hydrogen site occupancy, the electronic structure properties, and diffusion mechanisms. An improved method for observing the rigid-lattice proton lineshapes and extracting the second moments has been developed. Comparisions of the experimental second moments for polycrystalline samples with the values calculated from Van Vleck formulas for nuclear dipolar interactions have indicated that only tetrahedral interstitial sites are occupied by the protons in TiH/sub x/, ZrH/sub x/, crystalline TiCuH094, Ti2CuH19, and Zr2PdH/sub x/ (with x < 2) while both tetrahedral and octahedral sites can be occupied in amorphous a-TiCuH14, Ti2CuH26, and Zr2PdH/sub x/ (x > 2). The proton Knight shifts and low-temperature spin-lattice relaxation times have been related to the local densities of electron states at the Fermi levels N(E/sub F) in Ti/sub 1-y/V/sub y/H/sub x/, TiCr18H/sub x/, TiCr19H/sub x/, TiCuH/sub x/, Ti2CuH/sub x/, ZrH/sub x/, and Zr2PdH/sub x/. Chapters are devoted to the following subjects: Properties of Transition Metal Hydrides; Concepts and Methods of NMR as Applied to Metal Hydrides; A Simple Magic Echo Sequence for Second Moment Measurements; Proton NMR Lineshapes in ZrH/sub x/; Proton NMR Studies of Electronic Structure in Ti/sub 1-y/V/sub y/H195; Electronic Structure of Zirconium Hydride; Proton NMR and Magnetic Susceptibility Study of TiCr18H/sub x/; Proton NMR Studies of Hydrogen Diffusion and Electronic Structure in Crystalline and Amorphous Titanium - Copper Hydrides; and Proton Site Occupancies and Electronic Properties in Crystalline and Amorphous Zr2PdH/sub x/