When choosing a reliable benchmark level of theory for the subsequent TD-DFT study, the accuracy of a method must be considered alongside the time and resources needed to treat the system sizes involved in this study as well as the large number of points needed to generate smooth dissociation curves. As SCS-CC2/def2-QZVP calculations are feasible across all excimer systems, obtaining SCS-CC2/CBS(3,4) curves offers the potential for a reference at a standard comparable with ground-state studies. Ideally, to establish the accuracy of using this level of theory, we would want to obtain CCSDR(3)/def2-TZVP data for the larger excimer systems to offer a comparison. However, at this stage, our computational resources prevent this proposed extension. Given the low percentage errors for the benzene test case for truncated basis sets, discussed above, we obtain SCS-CC2 values for all excimers with TZ, QZ and CBS (3,4). Table lists the values of D e and r e from minima across these basis set treatments, while the corresponding dissociation curves are given as Figs . † Without higher-level data for all systems we cannot make a definitive statement as to the accuracy of these results. That being said, prior to extrapolation r e appears already close to convergence across all systems and D e differs within 0.11 to 1.52 kcal/mol.