Scaled theoretical IR spectra of mono PAH-C₆₀ adducts (one PAH unit: C₆₀-C_xH_y) modeled at the B3LYP-D3/6-31+G* level. All spectra were convolved with a Lorentzian function of FWHM = 0.02 μm. In the case of 2H-indene (In) and indenyl (Iyl), the blue and red arrows highlight the binding of the PAH with a pentagon and hexagon ring to the C₆₀ cage, respectively. For indenyl, with a single bond connecting its pentagon to C₆₀, a green arrow has been used instead. In all panels, the dashed red spectra correspond to the isolated pristine PAH, while the dashed blue lines mark the four strongest C₆₀ features (~7.0, 8.5, 17.4, and 18.9 μm). The black arrows on the spectra indicate those characteristic features (specific of each adduct), which are free of contribution from C₆₀, the pristine PAH and even from the other adducts.