Ab-initio approach to the many-electron problem

The chemical and physical properties of solids, molecules and nanomaterials depend on a subtle interplay of the spatial arrangement of the ions and the resulting distribution and density of electrons, which provide the binding forces of the system. Predicting the structure and the properties of novel materials, e.g., nanosystems, therefore is impossible without falling back on the elementary interactions and the most accurate ab initio methods for their simulation. We give a survey of the most popular ab initio methods used by quantum chemists, and describe some important modifications that made those methods available for the study of complex nanomaterials of moderate size.