The interaction of Fe and H, in the vicinity of a vacancy in body-centered cubic material, was studied within the framework of density functional theory. The results were compared with previous results which had been obtained by using semi-empirical molecular orbital methods. The calculations were performed by using an Fe cluster which contained 12 atoms and a vacancy. Geometrical optimization was used to find the most stable positions for one and two H atoms. Changes in the electronic structure of Fe atoms near to the vacancy were analyzed for the case where one and two H atoms were added to the Fe cluster. It was found that the Fe atom bonds which surrounded the vacancy were weakened when H was present. This was explained in terms of the formation of Fe-H bonds.

Density Functional Study of H–Fe Vacancy Interaction in BCC Iron. M.Estela Pronsato, C.Pistonesi, A.Juan: Journal of Physics - Condensed Matter, 2004, 16[39], 6907-16