where ε is the reference exciton energy, ϵ m is the onsite excitation energy for site m, and J mn is the diabatic coupling between site m and n. The diabatic states are represented in the exciton basis where |m⟩ ≡ |g 1 , g 2 , ..., e m , g m+1 , ..., g N ⟩ represents the exciton localized on the m th monomer