The C–C pair in the vicinity of a bcc Fe bulk vacancy:

S. SIMONETTI; M. E. PRONSATO; G. BRIZUELA; A. JUAN

PHYSICA STATUS SOLIDI B-BASIC RESEARCH

Wiley

Año: 2007 vol. 244 p. 610 - 618

0370-1972

C–Fe and C–C interactions near a bcc Fe vacancy were analysed using DFT calculations. A cell contain-ing 14 atoms was used to simulate the local  nvironment of the Fe vacancy. Carbon atoms were posi-tioned in their local energy minimum configurations. The most stable positions for the C atoms in the va-cancy region were found at about 1.23 Å from the vacancy centre and near the first nearest-neighbour oc-tahedralsites. Changes in the electronic structure of Fe atoms near a vacancy were analysed. Fe –Fe bonds surrounding the vacancy weaken their bond when the C atoms are present. This bond weakening is a con-sequence of C–Fe bond formation. The Fe–C interactions occur mainly via Fe 4s orbitals with a lesser participation of Fe 3p orbitals. There is an electron transfer to the C atoms from their Fe nearest neigh-bours. The C–C interaction was also analysed. For the C–C distance of 1.462 Å, there is a bonding be-tween the C atoms. The C –C interaction is stronger than the C –Fe interactions.