The H-Fe interaction in a dislocated body-centered cubic structure was studied by making qualitative electronic structure calculations in the framework of atom superposition and electron delocalisation molecular orbital theory. The effect upon the electronic structure, upon introducing an a/2[1¯11] mixed dislocation, was analyzed and was compared with the effect of introducing an a[010] edge dislocation. Calculations were performed by using Fe85 clusters to simulate a dislocated body-centered cubic structure. The cluster geometry and atomic parameters were optimized so as to ensure a better approximation to the repulsive energy terms. The most stable positions for two H atoms within the cluster were determined. The total energy of the cluster decreased when the H atoms were located near to the dislocation void; thus making it a possible region of H-accumulation. The H atoms bonded to their closest neighbors, weakening the bond between Fe atoms. The H-H interaction was also analyzed. In general the behavior of H, and its effect upon the Fe atom first-neighbors, appeared to have similarities for both of the dislocations analyzed.

A Comparative Study of the Electronic Structure of H pairs Near to a/2[1¯11] and a[010] Dislocations in BCC Fe. A.Juan, S.Gesari, G.Brizuela, M.E.Pronsato: Applied Surface Science, 2001, 182[1-2], 103-14