Here, P is the TDM in atomic orbital (AO) basis (computed with Multiwfn 3.8 ) and S is the AO overlap matrix. Diagonal elements F XX quantify contributions of local excitations and off-diagonal elements F XY , Y ̸ = X charge-transfer excitations (X, Y denote monomers of an aggregate). In what follows, we will express the FTDM elements in %, i.e. as F XY × 100 %. The overall CT contribution for a given transition was quantified as the sum of all off-diagonal FTDM elements,