where i represents either D e or r e . In this definition of percentage error, positive values represent overestimation while negative ones represent underestimation of the quantity. Fig. details the resulting signed percentage errors for D e (top panel) and r e (bottom panel). The numerical values and corresponding dissociation energy curves are given in Section SI.4. † As Fig. shows, the percentage errors in D e and r e are considerably large across all systems regardless of FE percentage. Almost all functionals underestimate D e , with a magnitude that tends to increase with amount of FE and system size, averaging across structures these errors range from about -83 to -38%. The size-dependence of the error can be partially explained with the fact that dispersion effects are expected to increase with system size and that dispersion corrections have not been applied at this stage. While percentage errors in r e are predominantly positive, negative errors seem to be associated more with higher amounts of FE, with average magnitudes ranging from 4 to 17%. Recovery of each minimum characteristic does not meet conveniently at the same functionals, i.e. a good description of r e is not accompanied by small errors in D e across all the functionals. Despite the overall poor performance from global hybrids regardless of FE percentage we can still gain an insight into the impact FE has for the complicated effects of excimer binding.