The study of actinide chemistry with multiconfigurational quantum chemical methods

The major contributions of Björn Roos to actinide chemistry, both in terms of quantum chemical method development and applications, will be reviewed. The extension of the complete active space SCF method followed by second order perturbation theory (CASSCF/CASPT2) method to a relativistic regime will be discussed, together with some of the most significant applications, like the study of U 2 and UO 2 .