Insights into the effects produced by doping of medium-sized boron clusters with ruthenium

Abstract

Modification of properties of boron nanoparticles by doping with transition metals presents a challenging problem because the number of isomers of both doped and un-doped nanoparticles rapidly increases with the nanoparticle size. Here, we perform a study of neutral and anionic Ru-doped boron clusters RuB_n (n = 9–20) using the unbiased CALYPSO structural search method in combination with density functional theory calculations. Our results show that the neutral RuB₉ cluster possesses a perfect planar wheel-like geometrical structure, whereas the RuB_n clusters prefer structures of the half-sandwich type in the range of 10 ≤ n ≤ 14, drum-like type in the range of 15 ≤ n ≤ 18 and cage-like structures for larger n values. The geometrical structures of the lowest total energy states of the RuB_n⁻ anions are similar to those of the corresponding neutrals, except for RuB₁₀⁻, RuB₁₁⁻, RuB₁₄⁻, RuB₁₅⁻ and RuB₂₀⁻. The neutral RuB₁₂ and RuB₁₄ clusters are found to exhibit enhanced stability with respect to the rest of the RuB_n clusters due to the delocalized bonding between the Ru atom and the boron host.