Local Geometric Effects on Stability and Energy Gap of Thiolate-Protected Gold Nanoparticles

Thiolate-protected gold nanoclusters, Au_m (SR)_n , have potential applications in many fields due to their high stability and remarkable electronic properties. However, the controlling factors in determining the stability and HOMO-LUMO gap of Au_m (SR)_n remain controversial, despite decades of work on the topic. Through DFT calculations, including nonlocal many-body dispersion (MBD) interactions, the geometric and electronic properties of Au_m (SR)_n clusters are investigated. Calculations demonstrate that the MBD interactions are essential for correctly describing the geometry and energy of the clusters. Greater anisotropic polarization and more atoms distributed in the shell of the clusters lead to more pronounced MBD interactions and higher stability of the clusters. Furthermore, the HOMO-LUMO gap of the clusters strongly depends on the gold core. These results provide critical clues for understanding and designing Au_m (SR)_n clusters.