Electron delocalization in clusters

Clusters are “ensembles of like objects or individuals,” according to the dictionary. In chemistry, it refers to aggregations of atoms or molecules that appear close together and are chemically interrelated. Clusters are made of a number of atoms or molecules, not too small and not too big, loosely referred to as “intermediate” between the molecular regime and the nanoparticle regime. Normally, the size of clusters ranges within the nanometer scale and consists of a hundred or so of atoms. Smaller ones are referred to as subnanometer clusters consisting of a few tens of atoms. All in all, clusters have a definite number and type of chemically interacting atoms in a specific geometrical arrangement, and consequently represent precise chemical species and studied as such. Herein, we shall concentrate in unveiling the close relationship between the electron delocalization of the valence electrons and the overall geometric structure of the clusters.