Electronic structure and adsorption stability of ferrocene on Au (111) and Ag (111) surfaces

Abstract The adsorption behaviours and electronic structures of ferrocene (Fc) on Au(111) and Ag(111) surfaces were investigated using density functional theory. Two Fc conformers, eclipsed (E-Fc) and staggered (S-Fc), were studied in vertical (⊥) and parallel (||) orientations at three adsorption sites: top, hollow, and bridge. Fc preferentially adsorbs in vertical configurations through the lower Cp ring at hollow sites, with adsorption energies of −0.87 eV and −0.79 eV for E-Fc on Au(111) and Ag(111), respectively, and −0.88 eV and −0.79 eV for S-Fc. Parallel configurations are less stable, with S-Fc failing to adsorb stably. Electronic structure analysis confirmed the presence of region-specific charge transfer electron circuits in the vertical configuration, which in turn enhanced the adsorption strength on the Au(111) surface. This unique electron circuit, absent in parallel configurations, contributes to the greater stability of vertical adsorption. Although Fc adsorption on the Ag(111) surface is slightly weaker compared to Au(111), similar adsorption trends and region-specific electron circuit characteristics are still observed, indicating comparable interaction mechanisms across both surfaces. These findings provide critical insights into Fc-metal surface interactions, laying a foundation for its applications in catalysis, corrosion inhibition, and surface modifications.