“Accurate Modeling of Diradical Systems’ Electronic Structure Requires Addressing Self-Interaction Error, Especially for Diradicals with Overlapping Orbitals”

https://pubmed.ncbi.nlm.nih.gov/38117018

This study finds that accurately modeling the electronic structure of diradical systems, including determining their open-shell character and singlet-triplet splitting, requires accounting for self-interaction error, particularly in cases where the relevant orbitals are in close proximity. However, for systems with well-separated electrons, such as (C21H13)2, conventional methods may suffice.