Computational study of the C–C interaction in the bcc Fe(001) inner plane containing a vacancy

S. SIMONETTI; G. BRIZUELA; A. JUAN

Materials Science-Poland

Polish Academy of Science

Lugar: Wroclaw; Año: 2007 vol. 25 p. 885 - 898

0137-1339

The C–Fe interaction in the (001) bcc Fe that contaning a vacancy was analyzed using a semiempirical theoretical method. A cluster model containing 125 atoms was used to simulate the local environment of the Fe vacancy. Carbon atoms were positioned in their local energy minima configurations. The most stable positions for the C atoms in the (001) bcc Fe were found at about 1.2 Å from the vacancy centre and close to the first nearest-neighbour octahedral sites. Fe atoms surrounding the vacancy weaken their bond when C is present. This bond weakening is a consequence of the C–Fe bond formation. The Fe–C interactions occur mainly via Fe 4s orbitals with a lesser participation of Fe 4p and Fe 3d orbitals. The C–C interaction was also analyzed. For the C–C distance of 1.4 Å, there is a possible bonding between the C atoms in the (001) bcc iron. The Fe–C interactions are stronger than the C–C interaction.