Abstract
Adsorption of 0.5 monolayer of N adatoms on W{100} results in a sharp (root 2 X root 2)R45 degrees LEED pattern. The only previous quantitative LEED study of this system gave a simple overlayer model with a Pendry R-factor of 0.55. An exhaustive search has been made of possible structures, including a novel vacancy reconstruction, displacive reconstructions and underlayer adsorption. From this work a new overlayer structure is derived with an R(p) value of 0.22, displaying a considerable buckling of 0.27 +/- 0.05 Angstrom within the second W layer and consequently involving large changes in the interlayer spacings of the surface. The N adatom is pseudo-five-fold coordinated to the W surface, bonding to a second-layer W atom with a nearest-neighbour bond length of 2.13 Angstrom and with the four next-nearest-neighbour W atoms in the surface plane at 2.27 Angstrom. The structure does not resolve the work function anomaly observed on this surface.
| Original language | English |
|---|---|
| Pages (from-to) | 272-278 |
| Number of pages | 7 |
| Journal | Surface Science |
| Volume | 325 |
| Issue number | 3 |
| Publication status | Published - 01 Mar 1995 |
Keywords
- CHEMISORPTION
- LOW ENERGY ELECTRON DIFFRACTION (LEED)
- SURFACE STRUCTURE, MORPHOLOGY, ROUGHNESS, AND TOPOGRAPHY
- ENERGY-ELECTRON-DIFFRACTION
- LEED STRUCTURE-ANALYSIS
- INDUCED RECONSTRUCTION
- SURFACE-STRUCTURE
- ALLOY