Global minimum structures and electronic stability of Pt-doped silicon clusters PtSi_n (n = 2 to 11) in neutral and anionic charge states

We report a systematic density functional theory investigation of neutral and anionic platinum-doped silicon clusters, PtSi_n, focusing on the size range n = 2–11. We obtained low-energy candidate geometries from a genetic-algorithm global search and we subsequently refined these structures with the PBE0/def2-TZVP approximation. For each cluster size, we identified the lowest-energy structures and summarised the resulting motif evolution and Pt coordination environments, providing a structure map for both charge states. We identified (i) size-dependent stability using binding energies and second energy differences, and (ii) a direct connection to anion photoelectron spectroscopy via calculated vertical detachment energies. Finally, real-space analyses within the Quantum Theory of Atoms in Molecules tracked dopant-driven charge redistributions, including the counterintuitive accumulation of negative charge at the Pt site and a pronounced anisotropy in the surrounding molecular electrostatic potential, which is qualitatively reminiscent of σ-hole-type descriptions invoked in halogen bonding. The combined structural, energetic, and spectroscopic data reported herein provide a reference set for future experiments and for further studies of Pt-doped silicon clusters.