Theoretical Aspects of the Electronic Structure and the Stability of Small Clusters

The investigation of the small clusters of metallic and nonmetallic elements shows that some clusters have some features common with the crystals (cluster bond lengths and cluster bond angles) and simultaneously other stable cluster forms exhibit very specific properties (for example, the planarity of Ia, IIIa, IVa‐tetramers, and Li6, Li7 clusters with pentagonal symmetries). The cluster stability and geometry can be generally well explained from the electronic properties of constituent atoms. Studies of the interactions of clusters with atoms and small molecules yield results which are interesting for the theory of chemisorption (for example, the donation, back‐donation picture of the CO‐metal interaction) and for the understanding of the electronic structure of organometallic compounds.