Theoretical study of thiol-induced reconstructions on the Au(111)
surface

Theoretical study of thiol-induced reconstructions on the Au(111) surface
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by L. M. Molina and B. Hammer.

Chem. Phys Lett. **360**, 264-271 (2002).

Abstract
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A new suggestion for the structure of the Au substrate underlying
Self-Assembled Monolayers (SAM) made of thiols is presented on the basis
of density functional theory results for methylthiolate (-SCH$\_3$)
adsorption on Au(111). It is found that by introducing vacancy defects
on the substrate, the adsorption of SCH$\_3$ is stabilized by about 0.8
eV with respect to the perfect Au(111) surface. As this overcomes the
vacancy formation energy ($\\approx$ 0.6 eV), a net driving force exists
leading to an adsorbate-induced reconstruction, that enhances adsorption
at defected Au(111). A comparison of results at high and low SCH$\_3$
coverage provides further insight into which specific gold vacancy sites
enhance the adsorption energy of the SCH$\_3$ molecule.