Structural Evolution and Electronic Properties of TaSi<sub><i>n</i><sup>–/0</sup></sub> (<i>n</i> = 2–15) Clusters: Size-Selected Anion Photoelectron Spectroscopy and Theoretical Calculations
Sheng‐Jie Lu, Hong‐Guang Xu, Xi‐Ling Xu, Wei‐Jun Zheng
Abstract
The structural evolution and electronic properties of TaSin–/0 (n = 2–15) clusters are explored using anion photoelectron spectroscopy accompanied by quantum chemical calculations. The Ta atom in TaSin–/0 is inclined to interact with more Si atoms and has high coordination numbers. The theoretical calculations show that TaSi2–/0 have trianglur structures and TaSi3–/0 adopt pyramid structures, while the geometries of TaSin–/0 (n = 4–7) are all exohedral structures dominated by bipyramid-based configurations with the Ta atom face-capping the Sin motifs. TaSi8–/0 and TaSi9–10– have boat-shaped geometries, whereas TaSi9–10 neutrals adopt bipyramid-based geometries instead of boat-shaped ones. TaSi11– and TaSi12 are confirmed as the critical size of transiting from exohedral to endohedral structures for anionic and neutral clusters, respectively. TaSi12–15–/0 have pentagonal or hexagonal prism-based geometries. Natural population analysis shows that the electron transfers from Sin skeletons to Ta atom. The second-order energy differences (Δ2E) and incremental binding energy (ΔEI) values exhibit strong odd–even alternations, suggesting that the TaSin-odd−/0 clusters are more stable than the adjacent TaSin-even−/0 ones, except that TaSi12–/0 are more stable than TaSi11–/0 and TaSi13–/0.