Structural Evolution of Palladium Clusters Pd₅₅^--Pd₁₄₇^-: Transition to the Bulk

Area of Science:

• Physical Chemistry
• Materials Science
• Nanotechnology

Background:

• Palladium clusters are crucial in catalysis and materials science.
• Understanding their structural evolution is key to controlling their properties.
• Previous studies have explored smaller palladium clusters, but a clear transition to bulk structures is less understood.

Purpose of the Study:

• To investigate the structural evolution of palladium cluster anions (Pd_n^-) from n=55 to 147 atoms.
• To determine the transition point from icosahedral to face-centered cubic (fcc) motifs.
• To correlate experimental observations with theoretical predictions.

Main Methods:

• Trapped ion electron diffraction (TIED) for experimental structural determination.
• Density functional theory (DFT) computations for theoretical modeling and validation.
• Analysis of cluster structures across a range of sizes (n = 55, 65, 75, 85, 95, 105, 147).

Main Results:

• Palladium cluster anions (Pd_n^-) exhibit a structural transition from icosahedral to fcc motifs with increasing size.
• Pd₅₅^- adopts an icosahedral structure, while Pd₁₄₇^- adopts the bulk fcc structure.
• A continuous increase in the fraction of fcc isomers was observed, with a crossover to the fcc motif around n ≈ 90.

Conclusions:

• The study elucidates the size-dependent structural evolution of palladium cluster anions.
• A clear transition from icosahedral to fcc structures occurs in the studied size range.
• The findings provide insights into the fundamental properties of metal clusters and their potential applications.