Lise Meitner Minerva Center for Computational
Quantum Chemistry
An important goal of our research is the creation of concepts and paradigms which are based on quantum chemistry and can guide experiment in new directions. We look for concepts which on the one hand lead to the understanding of a variety of facts in a unified way, and on the other hand, enable us to make predictions of new facts or trends which can be tested by experimentalists. Those interested should consult the list of publications provided in the site.
a) The effects or oriented external electric fields on reaction rate, mechanistic choice, and selectivity patterns.
b) New Bonding Concepts: Bonding is still not well understood. We identified new bonding mechanisms, so called "charge-shift bonding (CSB)" and "triplet-pair bonding (TPB)". Why do you breathe and do not catch fire? This is because the O2 molecule has a high charge-shift resonance energy (112 kcal/mol), which make its reactions generally endothermic, and hence the molecule is persistent. TPB is responsible for the existence of large clusters with high magnetic moments. When the cluster reaches 10 atoms, the strength of a single TPB can in turn reaches 40 kcal/mol or more. These clusters are important as they add a unique flavor to the chemical bond, and because they may also have technological usage.
c) Reactions of Metallo-Enzymes: Metallo-enzymes like Cytochrome P450 carry out essential life sustaining reactions such as oxygen capture, oxygen binding, oxidation of organic material to metabolically important species and as means of neutralizing toxic compounds. The field is full with exciting problems!
d) Two-state and multi-state reactivity (TSR and MSR). Many reactions of metallo-enzymes and catalysts proceed via two or more states. For example, the majority of nonheme enzymes utilize for catalysis complexes with high-spin (quintet states). We showed that the reason for this choice of Nature is the exchange-enhanced reactivity principle. This is a new principle of chemical reactivity. It is common in transition metals, but may well be observed in lanthanides and actinides.
e) Development of New Reactivity Concepts: Chemical thought is based on the valence bond (VB) theory. We are trying to develop new VB-based concepts and apply them to a variety of chemical problems.