Note that this figure also justifies the main calibration methodology presented in this section, of calibrating xTB-sTDA against TD-DFT. While xTB-sTDA was initially parameterized against mostly CC2 calculations, its accuracy is lower than TD-DFT with hybrid functionals such as PBE0, when compared to CC2. Because TD-DFT values are close in accuracy to CC2 values, calibrating xTB-sTDA to TD-DFT is a useful exercise. The functional B3LYP was chosen in this work due to the large amount of excited state data available using this functional, because it is less computationally intensive than range-separated hybrid functionals such as CAM-B3LYP. Calibrating against more accurate functionals or CC2 could be an avenue of future work.