The presence of open-shell transition metal centers adds substantial complexity to quantum-chemical problems. While density-functional theory provides a reasonably good treatment of dynamic and near-degeneracy correlation in transition metal-containing systems, few ab initio methods are able to do so for relatively large real-life systems, which translates to a fertile field for methods development and testing.
Catalysis and organometallic chemistry
Catalysis, whether homogeneous (this WP) or heterogeneous (addressed in cluster, surfaces and solids) is a key to future technologies. New catalytic processes provide efficient, selective, and environmentally benign production of essential chemicals and materials. The CTCC will focus on two areas of homogeneous catalysis that receive considerable attention today.
Dynamics and time development
Although the accurate calculation of energies and properties of molecules and solids is a prerequisite for reliable modeling, the time evolution of a system must be taken into account to model chemical reactions and rearrangement processes.
Large periodic and nonperiodic systems
Modern electronic-structure theory is well developed for the accurate treatment of small molecular systems, often with an accuracy rivaling that of experiment. For large systems, containing hundreds or thousands of atoms, for periodic systems (idealized solid-state and liquid systems) and for systems containing heavy atoms, the computational methods are less developed and incapable of yielding the high accuracy characteristic of small molecular systems. It is therefore important to develop an approach for the uniform treatment of large and small, periodic and nonperiodic, relativistic and nonrelativistic systems.
In many chemical modeling problems, only a small part of the full system needs t o be treated at a high level of accuracy; the remaining part of the system can be treated in a more approximate manner. Such models are said to be multiscaling, involving varying accuracy requirements in different regions of the chemical system. Our aim is the development of methods where different regions of space are treated at different resolutions and accuracies, thus allowing for a fully quantum-mechani cal partitioning of the molecular system without introducing arbitrary couplings between for instance a QM and a MM system. This can be realized through the use of scaling and detail (also known as wavelet) functions.
Properties and spectroscopy
Detailed insight into molecular structure and reaction dynamics is usually only possible by comparing theoretical data with spectroscopically observable properties. A particular concern of the CTCC is to ensure that new methodological advances are extended also to important spectroscopic techniques of relevance to its members, with emphasis on vibrational spectroscopies such as infrared and Raman spectroscopy, magnetic-resonance spect roscopies such as NMR and EPR, and X-ray spectroscopies such as XPS and XAS.