Qualitative representation of the assignments for the 10–15 µm AIBs and subcomponents. Top panel: Typical spectrum from the Orion Bar showcasing the AIBs. The insets show the decompositions for the 11.2, 12.0, and 12.7 µm AIBs. Middle panel: Proposed charge (color) and vibrational mode (marker) assignments of the 10–15 µm AIBs in terms of their carriers – PAHs or VSGs and/or PAH clusters, and vibrational modes. The “duo1” and “duo2” modes refer to the two modes that the duo CH_oop mode splits into in PAHs with only solo and duo hydrogens (Bauschlicher et al. 2008, 2009). Bottom panel: Boxes representing the theoretical ranges of CH_oop modes for small and large, cationic and neutral PAHs. The ranges for small (≲50 carbon atoms) cations and neutral PAHs are taken from Hony et al. (2001). The ranges for large (50–130 carbon atoms) neutral PAHs are derived from Bauschlicher et al. (2009, which is based on based on a small sample of PAHs), while those for their cationic counterparts are obtained from the NASA Ames PAH IR Spectroscopic Database (PAHdb) (Bauschlicher et al. 2010; Boersma et al. 2014; Bauschlicher et al. 2018). No redshift has been applied for these wavelength ranges. See text for details.