At EF , this is a poor approximation as almost all MOs contribute to the current density. Rather, it becomes a useful tool when we calculate the current density at ener-gies close to resonance features in the transmission, such as at the energy of the HOMO or the lowest unoccupied MO (LUMO). At a resonance, only a few MOs have a significant contribution to the current density. This fact allows us to distinguish between emergent features that arise from the combination of many MOs and features that are intrinsic to a given MO-gradient pair.