The PBE-based functionals generally yield larger dissociation energies than BLYP-based functionals and are closer to the reference despite still underestimating the excimer stability; for example, PBE20 yields errors in D e ranging between -62.1 and 3.4% while B3LYP errors range between -70.8 and -21.7%. A notable difference is seen for BLYP and BLYP75; they are unable to bind the anthracene and pyrene excimers. Interaction energy curves of CCS, which can be thought of as the HF equivalent for electronic excited states, were plotted to offer a comparison to a method with no electron-correlation but 100 % FE (see Fig. ). The CCS interaction energy curves possess only very shallow minima for the anthracene (D e = 0.31 kcal/mol) and pyrene (D e = 0.70 kcal/mol) excimers indicating that electron correlation plays a significant role in the stabilisation of those systems. PBEbased functionals can be thought to better describe the electron correlation contributions to the excimer states than BLYP based functionals. The difference between the two underlying XC functionals for the excimer state therefore parallels that of ground states, where PBE is more attractive than BLYP in the treatment of NCIs. No simple trend in performance with increasing FE is observed for the description of both D e and r e . Despite the generally improved performance of PBE based functionals, DFAs based on both XC expressions greatly underestimate the dissociation energy and overestimate r e with error trends that increase with FE and system size indicating the requirement of more sophisticated functionals for an accurate description of excimer binding. The ability of a global hybrid TD-DFA to describe each quantity seems to require a trade-off in accuracy to the other. As both D e and r e must be correctly described in order to predict excimer binding, global-hybrid TD-DFAs do not offer reliable results. Methods from the higher rungs of Jacob's Ladder and additive dispersion cor- rections have been effective in addressing some of short-comings associated with global hybrids for ground states, so their performance will be addressed in the following sections.