Exploring the structural and electronic properties of double-Fe atom-doped Si20 cluster by quantum chemical calculations

We carried out a quantum chemical investigation on the structural and electronic properties of double-Fe atom-doped Si-20 cluster by density functional theory calculations. The results showed that anionic, neutral, and cationic Fe2Si20 have similar Frank-Kasper structures, constructed by Si-4 rhombuses, Si-5 pentagons, and Si-6 hexagons. More interestingly, Fe2Si20- shows superhalogen properties. The Fe-Fe interactions in Fe2Si 20 -/0/+ (the meaning of the acronym: Fe2Si 20 -/0/+ refers to Fe2Si20 cluster with a negative charge, neutral state, and a positive charge, respectively.) are weak, further verified by constant electronic charge densities, molecular orbital, and PDOS analyses. The bonding interactions between atoms are in the sequence of Si-Si>Fe-Si>Fe-Fe. Moreover, Fe2Si20-, Fe2Si20, and Fe2Si20+ are all significantly aromatic.