Hydrogen Motion in Metals

The hydrogen atom on its interstitial site in the metal (or metal alloy or interme-tallic compound) generally may perform motional processes on very different time scales. At very short times the H atom vibrates against its metallic neighbors which, due to their much heavier masses, do not participate in these high frequency vibrations. Depending on H concentration and H-H interaction they can be considered either as local or optical modes. On the time scale of acoustic vibrations of the host lattice, the H atoms move more or less adiabatically according to the distortion pattern imposed by the host phonons and mirror the host density of states. This type of motion is also called a band mode. 

Experimental results for hydrogen diffusion coefficients and their relevance for the kinetics of hydrogen absorption are presented in Section 26.3. Section 26.4 

Hydrogen-Transfer Reactions. Edited by J. T. Hynes, J. P. Klinman, H. H. limbadi, and R. L Schowen Copyright 2007 WILEY-VCH Verlag GmbH Co. KGaA, Weinheim ISBN 978-3-527-30777-7 

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In this section we present a brief overview of experimental methods used to study hydrogen motion in metals. The methods giving microscopic information on the hydrogen jump motion are emphasized. We restrict ourselves to a discussion of the basic principles of these methods only. More detailed consideration of the application of different methods to studies of the hydrogen diffusion in metals can be found in the reviews [7-14]. 

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