Black lines show the average 600–1700 cm⁻¹ zero-Kelvin absorption (top panel) and emission spectra (middle and bottom panels) of the sixty selected pentagon-containing species in PAHdb. The bands have been convolved with a Gaussian line profile with a FWHM of 30 cm⁻¹. In the middle panel, a fixed red shift of 15 cm⁻¹ is used for each band, while in the bottom panel the shifts depend on frequency of the mode and maximum attained temperature. The 1σ variation around the mean is indicated by the gray shaded area and the average spectra for the anion, neutral and cation species alone are shown in red, blue, and green, respectively. Long-dashed lines are centered on the peaks of the features associated with bands at 9.3, 8.6 and 6.2 μm. See Sect. 4.2 for details.