Ab initio investigation of the clustering of carbon adatoms on Fe(001) and Fe(111) surfaces

A theoretical investigation of the interaction between carbon adatoms on the Fe(001) and Fe( 111 ) surfaces is performed using ab initio calculations in terms of density functional theory. Calc ulations of the adsorption energy demonstrate the existence of a strong bonding between single carbon adatoms and the iron surface. An analysis of the calculated energies of the interaction between carbon adatoms reveals for the first time that the repulsion between the carbon adatoms located at the nearest neighbor sites on the Fe(001) surface occurs and that clusters with a looser packing are formed on the surface.