Chemisorption of sulfur and sulfur-based simple molecules on Au(111)

A detailed study of the S-Au bond in different S and Au environments is presented. We find that the essential features of the S-Au bond are already contained in the simplest system, i.e., the S-Au dimer. A comparison of S, SH, and SCH3 adsorption on Au(111) reveals that functionalization of the S atom with -H or -CH3 influences only the adsorption geometry but not the character of the S-Au bond. On the basis of calculations at T = 0 K using a c(4 x 2) supercell, which contains four molecules, we also conclude that no significant interaction between adjacent molecules appears and, therefore, there is no tendency to dimerize or to form structures energetically more favorable than the (root 3 x root 3 )R30 degrees.