As most unscaled functionals underbind the pyrene excimer, both SCS and SOS tend to exacerbate this underestimation with larger deviations in D e compared to the benzene excimer. However, two of the three methods closest to the reference are spin scaled. As seen for benzene, the overbinding of ωPBEPP86 is favourably reduced by spin scaling, with SCS-ωPBEPP86 exhibiting the second smallest deviation in D e , 1.67 kcal/mol (5%) [Figure ]. Spin scaling also brings SCS-RSX-QIDH closer to the reference than the unscaled functional, reducing the deviation in D e from 8.42 (RSX-QIDH) to 3.35 kcal/mol [Figure ]. Spin-scaled methods are less likely to overbind, leaving room to account for dispersion with appropriate corrections.