ΔE =& accounts for the coupling between LE and CT states that is not negligible in typical face-to-face PAH aggregates. Following the definition of Zhao et al., we adapted the term "superexchange" (SE) to describe the variation in fluorescence energy after considering the CT states (E %&/+, model may not include all configurational state functions. These effects can be estimated by calculating the difference between the fluorescence energy computed by the exciton model with LE & CT states and that calculated by TDDFT: