An evaluation of bonding states of BCC (Fe) edge dislocation core by DV-Xα cluster method

Bonding states near the BCC (Fe) edge dislocation core based on the Peierls-Nabarro dislocation model have been studied by discrete variational (DV)-Xα method. The slip systems are {112}〈111〉 and {110}〈111〉. The molecular orbital calculation for the cluster models with 32 atoms belonging to the perfect crystal and Peierls edge dislocation core models were carried out for estimating bond order and net charge distribution among atoms in the cluster models. In {112}〈111〉 slip system total bond order between the nearest neighbor atoms of the dislocation model was found to be larger than that of the perfect crystal model. On the other hand, total bond order of the second neighbor atoms in dislocation model was a little smaller than that in the perfect crystal model. It was also found that there was asymmetry in the bond order between the left side and the right side of the (110) plane which contains the core atom of dislocation. Net charge in the dislocation model was larger than that in the perfect crystal model. Almost the same results were also attained for the {110}〈111〉 slip system.