The H-Fe interaction near to an edge dislocation line was studied by using qualitative electronic calculations within the framework of the atom superposition and electron delocalization molecular orbital theory. Calculations were performed by using a Fe207 cluster to simulate a dislocated body-centered cubic structure. The cluster geometry and atomic parameters were optimized in order to ensure a better approximation to the repulsive energy terms. The final localization of two H atoms within the cluster were determined as they entered from the (001) surface. The results indicated that the H-Fe interaction was stronger near to the dislocation; making it a possible region of H accumulation. Changes in the electronic structure of body-centered cubic dislocated Fe were analyzed for a system with no H, with one H atom or with two H atoms. The Fe atoms surrounding the dislocation line, which were initially more strongly bonded with each other than the bulk Fe atoms, weakened their bond when H was present. This was due to the formation of a H-Fe bond. The H influenced only its nearest Fe atoms.

The Electronic Structure and Location of H Pairs in a BCC Fe Edge Dislocation. M.E.Pronsato, G.Brizuela, A.Juan: Applied Surface Science, 2001, 173[3-4], 368-79