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.