Electronic Structure and Dynamics of Gold Nanoclusters

Thiolate-functionalized gold nanoclusters, in particular Au25(SCH3)18, are of considerable interest as catalysts for the hydrogen evolution reaction. In this work, the DFT method was used to investigate the effects of copper and palladium doping, as well as the role of the thiolate shell, on the atomic and electronic structures of the nanoclusters. It is shown that the low-symmetric configurations, in which the dopant atom (Cu or Pd) occupies the β position in the outer icosahedral layer of the cluster, are the most energetically favorable. For thiolate-functionalized clusters, stabilization of the central position (γ) is confirmed for Pd, whereas for Cu, substitution at the β position remains preferred. The electronic structure analysis shows that doping leads to a narrowing of the band gap, which may affect the chemical activity of the clusters. A machine-learning potential based on the DPA-2 descriptor was developed for modeling cluster dynamics, providing high accuracy (RMSE ~ 3 meV/atom) when reproducing DFT data. It is shown that for unfunctionalized clusters, the molecular dynamics optimization agrees well with the DFT results (RMSD 0.50 Å) related to the conformational flexibility of the ligands are observed.