Dissociative and non-dissociative adsorption of selenophene on Au(1 1 1) depending on the preparation method

Selenophene (C4H4Se) monolayers on Au(1 1 1) were prepared by two different methods: ultrahigh vacuum (UHV) and atmospheric vapor adsorption method. Near-edge X-ray absorption fine structure (NEXAFS) and X-ray photoelectron spectroscopy (XPS) results clearly indicate that the two monolayers are in different chemical forms; selenophene is molecularly adsorbed under UHV condition, while it is dissociatively chemisorbed via the C–Se bond cleavage under atmospheric condition. The dissociative chemisorption under atmospheric condition is interpreted in terms of the trapping mediated adsorption in the presence of a high-pressure ambient gas phase.