If the chromophores are spatially close, the assumption that all ESDs are strongly orthogonal is likely not fully warranted. However, even in this case, not all ESDs will violate the SOA equally. Thus, prior to the construction of the matrix H, one should attempt to detect the ESDs that violate the SOA most significantly, and expel them from the ECI basis. This sce-nario can easily occur if the site states on each chromophore are provided in a black-box manner (e.g., the first N F 0 singlet states, N F 1 triplet states, etc.). The lobes of some of those site states might significantly penetrate into the regions of the other fragments, and thus the ESDs including those site states might violate SOA more significantly than the others. The most pronounced example of such site states would be Rydberg excited states. To track such site states, one can use the integral