Structures and stabilities Ru-doped Ag_n (n = 1–13) clusters: Ag₁₀Ru a 18-ve cluster superatom

The geometrical and stability properties of Ru-doped silver clusters (Ag_nRu with n = 1–13) are investigated by density functional theory (DFT) calculations. The results show that the Ru dopant adopts central positions in the lowest-energy structures of Ag_nRu clusters. The most stable structures found are planar and curved for n = 3–6, while for n = 6 onward the structures follow a pentagonal growth pattern. Interestingly for n = 10, we found a cage structure with fulfills the 18 electron rule. The relative stability of the clusters is further evaluated through energetic parameters such as ionization energy, electron affinity, second order energy difference and HOMO–LUMO gap. The results show that the most stable structures in this series are Ag₃Ru, Ag₆Ru and Ag₁₀Ru, as supported by electronic structure analyses. The plausible formation of the Ag₁₀Ru cluster as a superatomic species is rationalized with 1.64 eV of HOMO–LUMO gap and 6.23 eV of adiabatic ionization energy.