The aim of the current project is to apply a theoretical approach, based on multiconfigurational wavefunction theory, to model high-resolution X-ray spectra of transition metal catalysts. The method correctly describes both multiplet effects and the effects of spin-orbit coupling. With our recent developments, we are now capable of modeling any X-ray process between bound states, including absorption, emission and inelastic scattering. The approach will be used to understand the electronic structure of transition metal complexes, in both static and time-resolved experiments. One target is to use X-ray spectra to verify catalytic mechanisms in water oxidation, including that of plant photosynthesis.