The structural and electronic properties of sulfur monomeric defects at the FeS2(100) surface have been studied by periodic density-functional calculations. We have shown that for a monomeric sulfur bound to an originally fivefold coordinated surface Fe site, the defect core features a triplet electronic ground state with unpaired spins localized on the exposed Fe-S unit. At this site, the iron and sulfur ions have oxidation states +4 and -2, respectively. This defect can be seen as produced via heterolytic bond breaking of the S-S sulfur dimer followed by a Fe-S redox reaction. The calculated sulfur 2p core-level shifts of the monomeric defects are in good agreement with experimental photoemission spectra, which allow a compelling assignment of the different spectroscopic features. The effect of water on the stability of the defective surface has also been studied, and it has been shown that the triplet state is stable against the wetting of the surface. The most important implications of the presence of the monomeric sulfur defect on the reactivity are also discussed.
Stirling, A., Bernasconi, M., & Parrinello, M. (2007). Defective pyrite (100) surface: An ab initio study. PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS, 75(16), 165406.
|Citazione:||Stirling, A., Bernasconi, M., & Parrinello, M. (2007). Defective pyrite (100) surface: An ab initio study. PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS, 75(16), 165406.|
|Tipo:||Articolo in rivista - Articolo scientifico|
|Carattere della pubblicazione:||Scientifica|
|Titolo:||Defective pyrite (100) surface: An ab initio study|
|Autori:||Stirling, A; Bernasconi, M; Parrinello, M|
|Data di pubblicazione:||apr-2007|
|Rivista:||PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1103/PhysRevB.75.165406|
|Appare nelle tipologie:||01 - Articolo su rivista|