Model cluster studies of the restructuring of the Fe(110) surface induced by the adsorption of carbon, nitrogen or oxygen

The EHT method has been used to calculate the energy of iron clusters, Fe-11, modelling the Fe(110) surface, as well as the energy of iron clusters with oxygen (Fe-11-O), nitrogen (Fe-11-N), or carbon atom (Fe-11-C), adsorbed on a reconstructed or non-reconstructed surface. To determine the relative positions of iron atoms and of the adsorbed atom a sphere model was employed assuming displacement of only one iron atom. ENT calculations show that the most preferential sites for oxygen, Nitrogen and carl,on adsorption are located on the non-reconstructed Fe(110) surface. The conceivable transition to the underlayer adsorption state would be an activated process. The activation energy for that transition for carbon atoms would be the greatest and for nitrogen atoms - the smallest one. The energy difference between the overlayer and underlayer adsorption state ranges in the sequence of increasing atomic number, The results are compared with calculations made earlier for (111) and (100) iron surfaces.