Do methanethiol adsorbates on the Au(111) surface dissociate?

TL;DR

This study investigates methanethiol adsorption on Au(111), revealing the S-H bond remains intact on perfect surfaces but breaks at defects, with implications for surface chemistry and catalysis.

Contribution

First computational evidence showing methanethiol does not dissociate on regular Au(111), only at defective sites, clarifying adsorption behavior.

Findings

S-H bond remains intact on regular Au(111)

Bond breaks at defective Au(111) surfaces

Methanethiol does not dimerize on regular surface

Abstract

The interaction of methanethiol molecules CH$_{3}$SH with the Au(111) surface is investigated, and it is found for the first time that the S-H bond remains intact when the methanethiol molecules are adsorbed on the regular Au(111) surface. However, it breaks if defects are present in the Au(111) surface. At low coverage, the fcc region is favored for S atom adsorption, but at saturated coverage the adsorption energies at various sites are almost iso-energetic. The presented calculations show that a methanethiol layer on the regular Au(111) surface does not dimerize.