Systematic theoretical investigation of structures, stabilities, and electronic properties of rhodium-doped silicon clusters: Rh₂Si _n ^q (n = 1–10; q = 0, ±1)

A systematic investigation of rhodium-doped silicon clusters, Rh₂Si _n ^q with n = 1–10 and q = 0, ±1, in the neutral, anionic, and cationic states is performed using density functional theory approach at B3LYP/GENECP level. According to the optimum Rh₂Si _n ^q clusters, mostly equilibrium geometries prefer the three-dimensional structures for n = 2–10. When n = 10, one Rh atom in Rh₂Si ₁₀ ^0,±1 clusters completely falls into the center of Si frame, and cage-like Rh₂Si ₁₀ ^0,±1 geometries are formed. The Rh₂Si _1,6–9 ⁺ and Rh₂Si _5,7,9 ⁻ clusters significantly deform their corresponding neutral geometries, which are in line with the calculated ionization potential and electron affinity values. The relative stabilities of Rh₂Si _n ^q clusters for the lowest-energy structures are analyzed on the basis of binding energy, fragmentation energy, second-order energy difference, and HOMO–LUMO gaps. The theoretical results confirm that the Rh₂Si₆ ⁻, Rh₂Si₆, and Rh₂Si₆ ⁺ clusters are more stable than their neighboring ones. The natural population analysis reveals that the charges in Rh₂Si _n ^q clusters transfer from the Si atoms to the Rh atoms except Rh₂Si⁺. In addition, the relationship between static polarizability and HOMO–LUMO gaps is discussed.