Interaction of Hydrogen with Defects in Metals: Interplay between Theory and Experiment

It is illustrated how an interplay between theoretical predictions and experimental measurements of binding energies or enthalpies and the corresponding equilibrium positions of hydrogen isotopes at defects in metals can lead to a new understanding of the microscopic structure of the observed hydrogen traps. Binding to vacancies and bubbles or voids is found to be strong, and a weaker trap is tentatively associated with self-interstitials. An extremely simple picture of the trapping process has evolved.