Comparison of the different adsorption states of non-metals on the iron surface

Abstract

The adsorption states of sulphur, phosphorus, carbon and nitrogen on the single crystal Fe(111) surface have been studied using the Auger electron spectroscopy. The AES spectra for high surface concentration of non-metals differ from these obtained for atomic adsorption states. The change of the AES line shape has been observed for all non-metals under the study. The observed changes have been explained on the basis of the model of the electronic structure and interpreted as a formation of the Fe-X-X bonds. For carbon and phosphorus a formation of three dimensional structure is observed. For sulphur adsorption and nitrogen segregation only a formation of X2 has been observed. The formation of X-X bonds weakens the iron-non-metal interaction. The effect of the coadsorbed electron-acceptor element (oxygen) on the state of the chemisorbed non-metal (sulphur) has been discussed, either.