Quantum chemistry methodology for the investigation of anisotropic exchange interaction in metal clusters

The aim of this project is to propose a methodology for the calculation and analysis of anisotropic exchange interaction in arbitrary polynuclear complexes involving lanthanide, actinide and transition metal ions. All developments will be based on the state-of-the-art quantum chemistry methods which are able to treat nowadays metal complexes of experimental relevance. First, the broken-symmetry (BS) density functional theory (DFT), which proved to be highly successful for the treatment of isotropic magnetic complexes, will be extended to treat anisotropic exchange interaction in complexes with arbitrary strength of spin-orbit coupling. To this end, the BS procedure will be implemented in the two-component version of DFT, in which spin-orbit coupling is taken into account. The second development concerns a microscopic approach to the evaluation and analysis of anisotropic exchange interaction in arbitrary polynuclear complexes which will combine ab initio and DFT calculations with detailed modeling of intercentre electronic interactions. The developed methodology will allow for the first time for a direct quantum chemistry evaluation of anisotropic exchange parameters in various polynuclear complexes, with an accuracy comparable to currently investigated isotropic exchange coupling. It will be applied within this project to the elucidation of anisotropic exchange coupling in several lanthanide, actinide and transition metal complexes of primary current interest.