Multilayer relaxations, surface/interface energies, and H binding sites and energies were systematically studied by applying the embedded-atom method to a series of clean or hydrogenated surfaces and symmetrical tilt grain boundaries. The H binding energies ranged from 2.7 to 2.9eV at surface sites, and from 2.1 to 2.6eV at grain-boundary sites. Both were larger than that (2.1eV) at face-centered cubic crystal interior sites. It was found that multi-layer relaxation played a key role in trapping H at grain boundaries.

Structure and Energetics of Clean and Hydrogenated Ni Surfaces and Symmetrical Tilt Grain Boundaries using the Embedded-Atom Method. M.Shiga, M.Yamaguchi, H.Kaburaki: Physical Review B, 2003, 68[24], 245402 (8pp)