Energetic Ground State Calculations, Electronic Band Structure at Surfaces

Ground-state properties and electronic band structures at surfaces are a very important field of research in surface science not only for catalysis, but more recently for organic electronics where several sensitive experimental techniques have been developed. Nowadays, a joint theoretical and experimental effort based on exceptionally improved computer power/algorithms and experimental advances is successful in describing adsorption sites, geometry, reconstruction, and many-body properties. In the first section, we focus on density functional theory (DFT) including its historical improvements: generalized gradient approximation, self-interaction correction, hybrid functionals (orbital-dependent functional), and phenomenological treatments of van der Waals (vdW) interaction. After examining the methods to compute band structures, we present organic classes of molecules. Polycyclic aromatic hydrocarbons have attracted significant interest for organic electronic devices, and are presented through examples of pentacene on silicon, noble metals, and aluminum. Charge rearrangement/dipoles/spin distributions induced by adsorption complete this chapter.