Complete active space analysis of a reaction pathway: Investigation of the oxygen-oxygen bond formation

Water nucleophilic attack is an important step in water oxidation reactions, which have been widely studied using density functional theory (DFT). Nevertheless, a single-determinant DFT picture may be insufficient for a deeper insight into the process, in particular during the oxygen-oxygen bond formation. In this work, we use complete active space self-consistent field calculations and describe an approach for a complete active space analysis along a reaction pathway. This is applied to the water nucleophilic attack at a Ru-based catalyst, which has successfully been used for efficient water oxidation and in silico design of new water oxidation catalysts recently.