The binary aluminum scandium clusters AlxScy with x + y = 13: when is the icosahedron retained?

Boron-doped scandium clusters B@Sc n-1 -/0/+ with n = 2-13: uncovering the smallest endohedrally doped cages

A comprehensive study using density functional theory with the PBE functional and the Def2-TZVP basis set investigates the pure Sc n +/0/- and doped Sc n-1B+/0/- clusters with n = 1-13 in three charged states. B@Sc6 +/0/- clusters emerge as the smallest doped cages identified so far, distinguished by their near-perfect octahedral geometry, with a B atom centrally enclosed in the Sc6 +/0/- cages. Structural analysis reveals size-dependent trends, with a critical size at n = 6, marking a transition from exohedral to endohedral configuration, and a shift in the substitution-addition pattern of the B atom within the pure Sc host. Incorporation of a B atom induces electron redistribution, stabilizes high spin states and reduces energetic degeneracy. B-doping enhances the stability of the initial Sc n +/0/- clusters, showing a consistent preference for cationic isomers. A molecular orbital (MO) analysis provides a detailed explanation for the observed energy degeneracy among various stable spin states by delving into their electronic configurations.

Geometric and Electronic Properties of P Atom-Doped Al Nanoclusters: Alkaline-like Superatom of P@Al12

The geometric and electronic characteristics of phosphorus-atom doped aluminum nanoclusters, AlnPm (n = 7-17, m = 1 and 2), were investigated through a combination of experiments and theoretical calculations. The size dependences of the ionization energy (Ei) for AlnPm NCs exhibit a local minimum of 5.37 eV at Al12P1, attributed to an endohedral P@Al12 superatom (SA). This SA originates from an excess electron toward the 2P shell closing (40e), coexisting with an exohedral isomer featuring a vertex P atom. The stability of the endohedral P@Al12 is further enhanced in its cationic state compared to the exohedral isomer, when complexed with a fluorine (F) atom, forming an SA salt denoted as P@Al12+F- with an elevated Ei ranging from 6.42 to 7.90 eV. In contrast, for the anionic Al12P1-, the exohedral form is found to be more stable than the endohedral one using anion photoelectron spectroscopy and calculations. The geometric and electronic robustness of neutral P@Al12 SAs against electron donation and acceptance is discussed in comparison to rare-gas-like Si@Al12 SAs.