Self-assembled monolayers of methylselenolate on the Au(111) surface: A combined STM and DFT study

In this study scanning tunneling microscopy (STM) and density functional theory (DFT) were used to investigate the structural formation of methylselenolate (CH3Se) self-assembled monolayers (SAMs) on the Au(111) surface. SAMs were prepared by two different methods, from solution and by exposing the Au(111) surface to gaseous dimethyldiselenide (DMDSe). For methylselenolate (MSe) on the Au(111) surface, our STM measurements revealed the presence of (4 × √3) and (3 × 2√3) rectangular striped phases. These structures were verified by DFT calculations. For both phases, the DFT calculations clearly found a bridge adsorption geometry for MSe on Au(111). Furthermore, they provide information about the electronic structure of the MSe–SAMs.