CRC 858 Z01 - Computational Chemistry: Theory and Modelling of Cooperative Phenomena in Chemical Systems

Basic data for this project

Description

Within the SFB 858 we describe the phenomenon "Cooperativity" on different levels of complexity of the respective systems. Systematic generation, manipulation and understanding of cooperative effects in chemical reactions afford detailed knowledge about the structural and energetic relationships on the molecular level. Modern quantum chemistry based molecular modeling methods have developed to powerful and reliable tools in recent decades for planning and interpreting chemical reactions. On the molecular level we define such arrangements being cooperative that consist of at least three components acting in concert (three-body-energy-cooperativity). Most of these systems may be utilized to activate chemical systems. For the analysis of energetic aspects of cooperativity, we need to define or generate (experimental or theoretical) reference systems that allow to measure cooperativity as an increasing or decreasing effect (the latter being defined as "anti-cooperative"): This effect then is described by a changed value of the (free) energy of the composite system, i.e. the overall mutual interaction energy δE(ABC) does not equal the sum over all pairwise {partial} interaction energies of its fragments (reference systems δE(AB), δE(AC), δE(BC)). (Anti)cooperativity then can be expressed as δE = δE(ABC) - δE(AB) - δE(AC) - δE(BC). In some cases it can be problematic or even impossible to investigate the reference systems experimentally. Then these shall be described by theoretical means. Quantum chemical methods of choice are based on density functional theory (DFT) and perturbation theory (MPn), respectively, as they have been established in the Grimme group (DFT-D, B2PLYP, SCS-MP2, MP2.5). As part of the project, existing methods shall be developed further and will be utilized in combination with efficient computer implementations (ORCA, TURBOMOLE and VASP codes) for various applications with other groups within the SFB. The project is sub-divided into a) non-covalent interactions, b) frustrated systems without transition metals, c) (bi)metalic systems and d) large systems and surface models.