Study of sulfur adlayers on Au(1Â 1Â 1) from basic hydrolysis of piperazine bis(dithiocarbamate) sodium salt

Sulfur adlayers on Au(1 1 1) were obtained after the interaction of a gold substrate with an alkaline solution of piperazine bis(dithiocarbamate) sodium salt. Characterization of the sulfur modified gold surface was performed by means of X-Ray Photoelectron Spectroscopy (XPS), Scanning Tunneling Microscopy (STM) and Density Functional Theory (DFT) calculations. XPS signals indicated the presence of S-Au bonds, monomeric and polymeric sulfur, and absence of nitrogen and sodium. Images from STM showed the formation of quasi-rectangular octomers in coexistence with another phase. A DFT model using the arrangement of sulfur dimers on the Au(1 1 1) surface effectively reproduced the experimental STM images.