Elements of a chemical orbital theory

Abstract

Interaction is important in chemistry. Interactions of atoms form chemical bonds. Bonds interact with each other in molecules to determine the molecular properties. Interactions of molecules give rise to chemical reactions. Electrons control atoms, bonds, and molecules. The behavior of electrons is simply and effectively represented by orbitals, which contain wave properties, i.e., phase and amplitude. In our chemical orbital theory we consider the interactions of the orbitals of atoms, bonds and molecules. The elements of the chemical orbital theory are separated into three groups: (1) interactions of two orbitals, (2) interactions of three orbitals, and (3) cyclic interactions of more than two orbitals. Here, general aspects of the interactions of two orbitals are summarized to show the background of this volume and assist nonspecialists to read the following chapters. Among the keywords are: phase and amplitude of orbitals, strength of orbital interactions, electron delocalization, electron localization, exchange repulsion, ionization energy, electronic spectrum, frontier orbitals, reactivity, selectivity, orbital symmetry, and so on. The remaining elements of the chemical orbital theory, i.e., an orbital mixing rule for the three-orbital interactions and an orbital phase theory for the cyclic interactions, are introduced briefly. © Springer-Verlag Berlin Heidelberg 2009.