Superatomic Signature and Reactivity of Silver Clusters with Oxygen: Double Magic Ag17- with Geometric and Electronic Shell Closure

Understanding the stability and reactivity of silver clusters toward oxygen provides insights to design new materials of coinage metals with atomic precision. Herein, we report a systematic study on anionic silver clusters, Ag-n(-) (n = 10-34), by reacting them with O-2 under multiple-collision conditions. Mass spectrometry observation presents the odd-even alternation effect on the reaction rates of these Ag-n(-) clusters. A few chosen clusters such as Ag-13(-) and Ag-17-19(-) hold up in the presence of excessive oxygen gas reactants. First-principles calculation results reveal that the chemical stability of D-4d Ag-17(-) is associated with its symmetric ellipsoidal structure and the electronic shell closure of superatomic orbitals (1S(2)vertical bar 1P(4 vertical bar)1P(2)vertical bar 1D(4)vertical bar 1D(6)parallel to 2S(0). This results in 17c-2e multicenter bonding and a large highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gap, the highest electron detachment energy and incremental binding energy among all the studied Ag-n(-) clusters, as well as the smallest O-2-binding energy and least charge transfer from Ag to O-2. We fully demonstrate the superatomic signature of these silver clusters and emphasize the unique Ag-17(-) with both geometric and electronic shell closure, shedding light on the 18e stability for the coinage of metal clusters. The superatomic charac teristics are also disclosed for Ag-16(-), Ag-18(-), and Ag-3(2)- clusters.

Automated summary

Understanding the stability and reactivity of silver clusters towards oxygen can offer insights for designing new materials of coinage metals with atomic precision. A systematic study on anionic silver clusters Ag-n(-) (n = 10-34) revealed odd-even alternation in reaction rates and stability of chosen clusters such as Ag-13(-) and Ag-17-19(-). First-principles calculations showed that Ag-17(-) exhibited unique characteristics with symmetric ellipsoidal structure and electronic shell closure, highlighting its 17c-2e multicenter bonding and high HOMO-LUMO gap.