Cr n Si15–n – (n = 1–3) clusters were investigated by using size-selected anion photoelectron spectroscopy combined with density functional theory calculations. The results show that the most stable structure of CrSi14 – is of C 2v symmetry with the Cr atom encapsulated in a Si14 cage which can be viewed as a boat-shaped Si10 unit capped by four additional silicon atoms. A large HOMO–LUMO gap of neutral CrSi14 is confirmed based on the photoelectron spectrum of CrSi14 – anion. Cr2Si13 – has two isomers nearly degenerate in energy: one can be characterized as one Si atom interacting with a Cr2Si12 hexagonal prism while the other can be viewed as one Si atom capping a distorted Cr2Si12 hexagonal antiprism. Cr3Si12 – has a D 6d symmetric wheel structure in which three Cr atoms form an axle surrounded by 12 Si atoms. The magnetic moments of CrSi14 –, Cr2Si13 –, and Cr3Si12 – increase from 1 to 3 μB and then to 7 μB with the increasing number of Cr atoms in the clusters. The magnetic moments of Cr2Si13 – and Cr3Si12 – are mainly contributed by the surface Cr atoms.

The structural, electronic, and magnetic properties of FeGe (n = 3-12) clusters were investigated by using anion photoelectron spectroscopy in combination with density functional theory calculations. For both anionic and neutral FeGe (n = 3-12) clusters with n ≤ 7, the dominant structures are exohedral. The FeGe clusters have half-encapsulated boat-shaped structures, and the opening of the boat-shaped structure is gradually covered by the additional Ge atoms to form Ge cage from n = 9 to 11. The structures of FeGe can be viewed as two Ge atoms symmetrically capping the opening of the boat-shaped structure of FeGe, and those of FeGe are distorted hexagonal prisms with the Fe atom at the center. Natural population analysis shows that there is an electron transfer from the Ge atoms to the Fe atom at n = 8-12. The total magnetic moment of FeGe and local magnetic moment of the Fe atom have not been quenched.

Experimental measurements and theoretical calculations show that CoSi10− has the highest vertical detachment energy among all the CoSin− (n = 3–12) clusters, implying CoSi10− has special stability.