Magnetic properties of actinide complexes from first principle calculations.

Magnetic properties of actinides are often analyzed using models devoted to lanthanides. But due to the higher covalency of the former, those models are not adequate and a more precise description of the complexes is necessary in order to get the full understanding of those properties. The calculation of the magnetic properties of open-shell 5f molecules is a challenge for the methods of quantum chemistry: actinide complexes have many low lying configurations, spin-orbit effects are important and correlation effects must be taken into account. The first principle SO-CASPT2 method gives results that compare well to experimental data and permits to analyze the different contributions to the magnetic properties.

On monomers, calculations enable to
- determine crystal field parameters
- analyze the effect of covalency
- scrutinize the contributions above the LS coupling scheme.

On dimers, they permit to
- analyze the magnetic coupling between the two magnetic centers
- propose Spin Hamiltonians which permit to model the magnetic behavior of those complexes