Fig. 7.

Energy diagram of Au replacement sites in Ag₄₄ nanoclusters. The Ag atoms of [Ag₄₄(SR)₃₀]⁴⁻ (SR denotes thiolate ligand) are ordered into three general groups, the core Ag (gray), the intermediate shell Ag (light blue) and the outer shell Ag (purple). The sulfur (orange) atoms are shown, but the hydrocarbon tail and carboxylic ligand groups have been omitted for clarity. The relative energies for Au replacement on each of the three regions are labeled as shown