Exploration of the interaction strength at the interface of neutral chalcogen ligands and gold surfaces.

Using dispersion-corrected density functional theory (DFT-D3), this study systematically examines the adsorption behavior of Au(XR) species (X = S, Se, Te; R = -H, -CH3, -C6H11) on gold surfaces of different morphologies Au(111), Au(100), Au(110), Au(321), and Au(321̄). The results demonstrate that the interaction strength increases with both the chalcogen's polarizability and the steric size of the substituent (Te > Se > S and -H < -CH3 < -C6H11). A clear relationship between surface reactivity and dispersion contribution is established: while Au(111) adsorption is governed by long-range van der Waals interactions, rougher surfaces such as Au(110) and Au(321) promote stronger chemisorption through bridge-type bonding. Notably, a dispersion threshold of approximately 45% distinguishes between physisorbed and chemisorbed regimes. Bader charge and PDOS analysis further reveals charge transfer from the metal slab to the ligand, increasing from S to Te. These findings offer a comprehensive structure-energy relationship that can guide the rational engineering of chalcogen-gold interfaces with tailored electronic and structural properties.