Azimuthal dependence of the near-edge x-ray-absorption fine structure from Ni(110)c(2×2)-S at the SKedge
| Autor: | C. H. Richardson, G. Thornton, D.R. Warburton, Ronan McGrath, D. Norman |
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| Rok vydání: | 1991 |
| Předmět: | |
| Zdroj: | Physical Review B. 43:12289-12295 |
| ISSN: | 1095-3795 0163-1829 |
| Popis: | The near-edge x-ray-absorption fine structure (NEXAFS) observed at the S K edge from Ni(110)c(2\ifmmode\times\else\texttimes\fi{}2)-S exhibits a strong dependence on the azimuthal as well as the polar orientation of the x-ray electric vector. Such a marked azimuthal dependence has not been observed from other atomic adsorbate systems, suggesting that the NEXAFS may arise from pseudointramolecular resonances. However, this interpretation is shown to be inadequate by comparison of experimental data with multiple-scattering calculations. The calculations show that the NEXAFS above the white line is determined in a complicated way by several shells of neighboring atoms, and is not simply dominated by sulfur-nickel near-neighbor scattering. Despite this, the calculations do show that the NEXAFS is sensitive to the adsorption site, and therefore complement the surface extended x-ray-absorption fine-structure information. The calculations do not, however, describe the white line accurately and hence its origin remains to be determined. |
| Databáze: | OpenAIRE |
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