Computation of Magnetic Exchange Couplings in Photoexcited Systems Based on KS-DFT

Many efforts have been made in the study of optically excited spin-coupled molecules due to their appealing features for quantum information sciences. However, the characterization of the magnetic exchange couplings occurring from the photoexcitation is challenging experimentally. In this context, theoretical determinations play a critical role and must provide evaluations with rigorous and cost-effective strategies. This work presents a new approach to compute magnetic exchange couplings in photoexcited systems based on the recently generalized decomposition/recomposition method (David et al., Phys. Chem. Chem. Phys. 2024, 6, 8952−8964). This corresponds to the first application of KS-DFT in this context and offers both a completely general method and a powerful rationalization tool. This strategy is applied to mono- and biradical-based molecules recently synthesized by Kirk and co-workers.