Münster 1997 – wissenschaftliches Programm
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O: Oberflächenphysik
O 3: Adsorption von N und O
O 3.5: Vortrag
Montag, 17. März 1997, 10:30–10:45, S 2
Adsorption of Nitrogen on Ru (0001) — •Ari P Seitsonen and Matthias Scheffler — Fritz-Haber-Institut der MPG, Faradayweg 4–6, D–14195 Berlin–Dahlem
We have studied the adsorption of atomic nitrogen on Ru (0001). The resulting geometries, binding energies, diffusion barriers and vibrational frequencies agree well with the experimental results from LEED, STM and EELS, and a simple tight-binding model is shown which is able to describe the strong bond of the adsorbed atom to the substrate [1]. The very high binding energy of the N2 dimer, however, limits the highest obtainable coverage, which is about Θmax ≈ 0.6. This is in contrast to O/Ru (0001) where a coverage of a full mono-layer was reported [1]. The adsorbate-adsorbate interaction is repulsive at coverages > 0.25 and attractive at Θ = 0.25.
Furthermore, we present results for the hydrogenated nitrogen (NH) on Ru (0001) and a mixed phase of N and NH, and discuss the implications to the Haber-Bosch synthesis of ammonia.
[1] S. Schwegmann et al., submitted to Chem. Phys. Lett.
[2] C. Stampfl et al., Phys. Rev. Lett. 77, 3371 (1996).