Adsorption of methanethiol on Au(111): Role of hydrogen bonds

Through Density Functional Theory calculations (with and without long range dispersion corrections) we investigate and compare the stability of a large set of structures involving methanetiol molecularly adsorbed on Au(1 1 1). In particular, we consider possible cooperative effects like the formation of dimers and chains of molecules interacting through SH...SH H-bonds. We conclude that structures of dimer H-bonds are the most stable ones for molecular coverages 1/6 less than or similar to theta <= 1/3. For this range of coverages, a dimer H-bond moiety can act as a precursor for the S-H bond scission process through a cooperative H transfer mechanism. (C) 2014 Elsevier B.V. All rights reserved.