Diffusion of the Linear CH₃S−Au−SCH₃ Complex on Au(111) from First Principles

Recent experimental and computational advances have clearly established the importance of the linear alkylthiolate−Au−alkylthiolate (RS−Au−SR) complex at the interface between the thiolate groups and the gold surface. By using density functional theory-based first principles method, here we show that the elementary diffusion step of this linear complex on Au(111) has a barrier of only ∼0.5 eV in the case of methylthiolate, indicating great mobility of the linear complex on Au(111). The role of this low barrier in the formation of a self-assembled monolayer of thiolate groups in the form of RS−Au−SR on Au(111) is discussed.