Beyond the binding region, in the medium-to-long range inter-monomer separation, TD-DFA interaction energy curves falsely predict a repulsive region. For the benzene excimer, all functionals as well as SCS-CC2/def2-TZVP exhibit that positive region falling between 4.3 Å and the asymptote. An extrapolation of SCS-CC2 to the CBS limit [CBS (3,4)] mostly corrects the unphysical repulsion of SCS-CC2/def2-TZVP, reducing the repulsion to less than 0.01 kcal/mol, which is way within the expected numerical noise for that method and a negligible value (see Fig. ). Larger excimers exhibit a similar repulsive region for global hybrids and range-separated hybrids (see Figs. S14-S17 † for further details). Herein, we focus on the benzene excimer by observing B3LYP and B2PLYP with and without dispersion corrections in the range between 4.00 and 12.00 Å (Fig. ). The extent of the repulsion for dispersion-uncorrected B3LYP is over twice that of B2PLYP, with maxima of 0.35 and 0.12 kcal/mol, respectively. The D3(BJ) correction reduces the repulsion yielding maxima of up to 0.02 kcal/mol, which brings the two functionals into close comparison with each other (maxima within 0.001 kcal/mol of each other). The D4 curves are also comparable in this region, although they exhibit larger maxima than D3(BJ) curves: 0.07 and 0.06 kcal/mol for B3LYP-D4 and B2PLYP-D4, respectively. The positive behaviour that remains after the applied corrections would not be expected with corrections appropriately parametrised for excited states. Interestingly, in a recent study of exciplex interaction energy curves, a similar unphysical repulsive hump exhibited by ωB97 also saw correction by ωB97X-D3 196 with DFT-D3(0), something that has not been noticed by the authors. As excimer binding is comprised of more than just dispersion effects, 8 dispersion-uncorrected functionals are able to predict some attraction in the binding region, with more complex functionals performing reasonably in binding the benzene excimer. In the medium-range, however, the dispersion-uncorrected functionals predict an unphysical repulsive region. Medium-range inter-monomer separations appear to be governed by dispersion, and can therefore only be accounted for by inclusion of the dispersion energy missing from the description by dispersion-uncorrected TD-DFAs.