Theoretical modeling and calculation of structures and chemical systems represents an important tool in the field of surface-driven reactions, especially in conjunction to imaging studies. The calculated structures and energies allow deep insights into adsorption phenomena, the potential surfaces of the reactions and support the interpretation of STM and AFM data. Density functional theory (DFT) represents the method of choice for obtaining an atomistic understanding. An extension of the DFT calculations, for example with a modeled tip related to AFM-generated images, allows the generation of experiment-like images for direct comparison. The insights gained into the reaction mechanism, energetics, and possible side reactions allow for an optimization of the reactions and molecular structures as well as a systematic classification.
Scientific Goals
While in subprojects B, C, D and E the existing possibilities of atomistic modeling are already used to answer specific questions, the aim of this project area is to validate and extend these methods and to use them for molecular design. In the first focus of method validation, density functionals and dispersion corrections as well as semiempirical methods are assessed for their accuracy in describing geometric adsorption structures and energetics. The second focus is the modeling of larger extended systems to account for aspects such as the curvature of nanostructures that are not or insufficiently captured in current modeling. This will lead to a better understanding in the design of nanostructures and reactions. The third focus represents the systematic investigation of important elementary steps with respect to the variation of the molecules, for example by the variation of the substituents or the number and position of a heteroatom in the ring systems, or the surface. For this purpose, an efficient screening method is developed, which allows to establish structure-reaction relationships and to derive general concepts for molecule selection for surface-assisted synthesis.
