Electronic Structure and Properties of Molecules and Clusters: Density Functional Theory Based Approach

A theoretical basis for the concepts of chemical reactivity, selectivity and stability of molecular complexes has been discussed within the framework of density functional theory. In particular, special attention has been focused on the development of a theoretical formulation to establish a relation between the total energy changes with respect to the changes in the chemical potential and hardness parameters. A model based on local hard-soft-acid-base principle has been proposed to evaluate the intermolecular interaction energy of the molecular complexes in terms of the reactivity descriptors. In addition, we have also presented the quantum size effects on the electronic response properties of alkali metal clusters and some issues on the effects of electron correlation in the evaluation of the polarizability of these clusters. Further, we have briefly outlined the concept of magic clusters and their potential use as building blocks of cluster-assembled materials.