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

The geometric and electronic characteristics of phosphorus-atom doped aluminum nanoclusters, AlP ( = 7-17, 1 and 2), were investigated through a combination of experiments and theoretical calculations. The size dependences of the ionization energy () for AlP NCs exhibit a local minimum of 5.37 eV at AlP, attributed to an endohedral P@Al 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@Al 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@AlF with an elevated ranging from 6.42 to 7.90 eV. In contrast, for the anionic AlP, 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@Al SAs against electron donation and acceptance is discussed in comparison to rare-gas-like Si@Al SAs.