Expansion of applications of ab initio methods for transition metal complexes.

This project is aimed at further opening up new possibilities for quantum chemistry in the field of relatively large inorganic systems of biological importance, such as those found in metallo-enzymes. Currently, density functional theory is the method of choice for a lot of these molecules, mostly because of the cheap computational cost with respect to the size of the systems. Fortunately, recent improvements have made it possible to reduce the computational cost of ab initio methods, thereby enabling the study of larger systems commonly found in bio-inorganic chemistry. As most of these molecules are characterized by a complex open-shell electronic structure, the use of ab initio methods can often provide a valuable and more accurate alternative to density functional theory. One of those ab initio methods is multiconfigurational perturbation theory, which is implemented in the program MOLCAS. However, despite the succes of the recently introduced restricted multiconfigurational perturbation theory in the program, there is still a need for improvement. In a first step, we want to solve some issues related to the implementation itself, and in a second phase we will study biologically relevant transition-metal complexes which were so far inaccessible to ab initio wave function methods, in particular (i) transition metal ions with high oxidation states in combination with large pi-conjugated ligands, and (ii) systems with multiple transition metal centers.

Keywords:Transition metal complexes