Averaged theoretical harmonic IR spectra for PAHs containing 1–10 hexagons in neutral (N), cationic (C), and anionic (A) charge states in cata- and peri-condensed forms in the gas phase. The same three spectral regions are shown: (a) 3.0–3.4 μm, (b) 6.0–9.0 μm, and (c) 11.0–13.0 μm. Observational data are obtained from JWST and are processed using baseline correction, emission-line suppression, and normalization. Dotted vertical lines indicate the observed positions of AIBs.