Density Functional Investigation of the Inclusion of Gold Clusters on a CH3S Self-Assembled Lattice on Au(111). (17th October 2016)

• Record Type: Journal Article
• Authors: Allen, Darnel J.; Archibald, Wayne E.; Harper, John A.; Saputo, John C.; Torres, Daniel
• Other Names: Mishra Abhishek K. Academic Editor.
• Is Part Of: Advances in chemistry. Volume 2016(2016)
• Publication Date: 2016-10-17
• Subjects: Chemistry -- Periodicals; Chemistry; Periodicals; 540
• DOI: 10.1155/2016/6080343
• Languages: English
• ISSNs: 2356-6612

Abstract

Abstract : We employ first-principles density functional theoretical calculations to address the inclusion of gold (Au) clusters in a well-packed CH3 S self-assembled lattice. We compute CH3 S adsorption energies to quantify the energetic stability of the self-assembly and gold adsorption and dissolution energies to characterize the structural stability of a series of Au clusters adsorbed at the SAM-Au interface. Our results indicate that the inclusion of Au clusters with less than four Au atoms in the SAM-Au interface enhances the binding of CH3 S species. In contrast, larger Au clusters destabilize the self-assembly. We attribute this effect to the low-coordinated gold atoms in the cluster. For small clusters, these low-coordinated sites have significantly different electronic properties compared to larger islands, which makes the binding with the self-assembly energetically more favorable. Our results further indicate that Au clusters in the SAM-Au interface are thermodynamically unstable and they will tend to dissolve, producing Au adatoms incorporated in the self-assembly in the form of CH3 S-Au-SCH3 species. This is due to the strong S-Au bond which stabilizes single Au adatoms in the self-assembly. Our results provide solid insight into the impact of adatom islands at the CH3 S-Au interface.