DFT-simulated IR (~3–25 μm) spectra of the mixture of PAH-C₆₀ adducts. (A) Total (summed) mixture spectrum; (B): total abundance-weighted spectrum using the indene abundance from Burkhardt et al. (2021); and (C) total abundance-weighted spectrum using the indene abundance from Cernicharo et al. (2021). In all panels, the dashed red lines mark the most common astronomical PAH features (at ~3.3, 6.2, 7.7, 8.6, 11.2, and 12.7 μm), instead dashed blue lines mark the four strongest C₆₀ features (~7.0, 8.5, 17.4, and 18.9 μm. In the case of the total (summed) mixture spectrum, the intensity has been normalized to the maximum intensity peak, while the abundance-weighted spectra have been normalized with respect to the higher intensity peak from the weighted spectrum (C); i.e., the one using the indene abundance from Cernicharo et al. (2021).