| 1. |
- Andersen, J. N., et al.
(författare)
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Surface core-level shifts of some 4d-metal single-crystal surfaces : Experiments and ab initio calculations
- 1994
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Ingår i: Physical Review B (Condensed Matter). - 0163-1829. ; 50:23, s. 17525-17533
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Tidskriftsartikel (refereegranskat)abstract
- High resolution measurements are reported of the surface core-level shift of the 3d level for the Rh(111), Rh(110), Pd(111), Pd(110), and Ag(111) single-crystal surfaces. These measurements and earlier ones for the Mo(110), Rh(100), and Pd(100) surfaces are analyzed by ab initio calculations of the surface core-level shift. The calculations are found to reproduce well the trends of the experimental shifts with the 4d metal and with the crystal plane. The comparison between these experimental and theoretical results demonstrates the importance of proper inclusion of final-state effects for accurate calculations of surface core-level shifts. A core hole in a surface atom is found to be better screened than one in a bulk atom for the 4d metals to the left of Pd in the Periodic Table. The use of the Z+1 approximation to describe the core hole is investigated both by explicit use of this approximation and by performing calculations for 1s and 3d core holes, respectively. The Z+1 approximation is found to be well obeyed in the case of Ag whereas for the rest of the 4d transition metals it is less precise, introducing errors of typically 0.1 eV.
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| 2. |
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| 3. |
- Heskett, D., et al.
(författare)
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Alkali-alkali interactions on Al(111) : segregation and islanding in Na-Rb mixtures
- 1994
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Ingår i: Surface Science. - 0039-6028. ; 316:3, s. 303-308
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Tidskriftsartikel (refereegranskat)abstract
- The low temperature coadsorption of Na and Rb on an Al(111) surface is examined with a combination of LEED and core level photoemission spectroscopy. We observe LEED pattern sequences and alkali core level binding energies which are consistent with a net total alkali coverage and can be explained by Na-Rb repulsion, segregation, and islanding, though other models cannot be definitely excluded.
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| 4. |
- Lundgren, E., et al.
(författare)
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Alkali core-level binding-energy shifts in alkali/4d-metal interface systems
- 1994
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Ingår i: Physical Review B (Condensed Matter). - 0163-1829. ; 50:7, s. 4711-4717
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Tidskriftsartikel (refereegranskat)abstract
- Photoemission from different alkali core levels (Na 2p, K 3p, Rb 4p, and Cs 4d) has been studied for thin alkali films deposited on four different 4d metal surfaces: Mo(110), Rh(111), Rh(110), and Pd(100). Alkali atoms at the interface, the bulk, and at the surface of the adsorbed alkali film are found to have different core-level binding energies. It is found that the core-level binding-energy shifts of the alkali metals induced by the 4d-metal substrate increase with increasing atomic number of the alkali metal and with increasing atomic number of the 4d metal. Thermodynamical quantities such as interface segregation energies and adhesion energies are deduced from the layer-resolved shifts. Estimates of the experimental binding-energy shifts are given using semiempirical calculations, and certain complications in doing that are discussed.
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