Geometry and Charge State of Mixed‐Ligand Au13 Nanoclusters

The integration of synthetic, experimental and theoretical tools into a self‐consistent data analysis methodology allowed us to develop unique new levels of detail in nanoparticle characterization. We describe our methods using an example of Au 13 monolayer‐protected clusters (MPCs), synthesized by ligand exchange methods. The combination of atom counting methods of scanning transmission electron microscopy and Au L3‐edge EXAFS allowed us to characterize these clusters as icosahedral, with surface strain reduced from 5% (as in ideal, regular icosahedra) to 3%, due to the interaction with ligands. Charge transfer from Au to the thiol and phosphine ligands was evidenced by S and P K‐edge XANES. A comparison of total energies of bare clusters of different geometries was performed by equivalent crystal theory calculations.