The adsorption of adenine on Cu(110), Ag(110) and Au(110) has
been investigated comparatively with the focus on the nature of the
molecule-substrate interaction.
For the adsorption on Ag(110) and Au(110), similar geometries
as for Cu(110) [1] have been found. However, in both cases the
molecule tends to a flatter position and a large distance from the
substrate, indicating a weaker interaction, which also manifests itself
in reduced binding energies compared to Cu.
Based on a detailed analysis of the charge transfer, we have
calculated the contributions of the interactions of the
induced dipoles and monopoles.
While in case of Cu a strong relaxation of the binding surface-atom
plays an important role in the bond formation, an increasing
electrostatic effect and less surface relaxation has been observed
for the more noble Ag- and Au-surfaces.
[1] M. Preuss, W.G. Schmidt, and F. Bechstedt,
Phys. Rev. Lett. 94, 236102 (2005).
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