Chemisorption of molecular sulphur (S 2) on Ni(001)

Abstract

The adsorption of sulphur from a molecular (S 2) beam onto the Ni)001) face was investigated using low energy electron diffraction, Auger electron spectroscopy and measurements of changes in the work function. For low coverages of sulphur the low energy electron diffraction patterns show some features not previously observed during the adsorption of sulphur from gaseous H 2S. These features indicate that p(2 × 2) narrow sulphur islands elongated in the [10] and [01] directions are formed. A dependence of the adsorption rate on the sample temperature and the formation of antiphase domains, previously observed for sulphur adsorption on the Ni(110) face, were not found in the present work for the Ni(001) face. The mean free path of Ni M 2,3VV Auger electrons ( E = 60 eV) in the sulphur layer was estimated to be between 1.7 and 5 monolayers.