Hydrogen in metals: screening, resistivity, and diffusion
Shaw, Milton Samuel
Lane, Neal F.
Master of Arts
The theory of screening of a potential in various approximations of a metal are reviewed. Phase shifts were calculated for free electron scattering by a Yukawa potential, and the screening parameter was adjusted to satisfy the Friedel sum rule. Using these phase shifts, residual resistivities of hydrogen in various metals were calculated in qualitative agreement with experiment. The theories of diffusion of hydrogen in metals are reviewed. A model for the hydrogenmetal interaction has been constructed using linear response screening for the hydrogen and superposition of neutral atoms for the metal. Screening in the region of the metal cores was treated with a pseudopotential. The occupation of octahedral sites in FCC metals and tetrahedral sites in BCC metals is correctly predicted. Vibrational energy level spacing for Pd and Ni were calculated to be .8 eV and .16 eV, respectively. Experimental values are .6 eV and .12 eV. Activation energies for diffusion are estimated with qualitative agreement with experiment.