Infrared spectra for the pretzels and cages families. (a), (b) Zoom into the [2.8 - 4 µm] region. The intensities were multiplied by 4 for C₂₄H₆ and by 2 for C₂₄H₁₂ to make the structures of the bands visible. (c), (d) The features represented with dashed lines in the [10.2 - 22.7 µm] region were rescaled using the appropriate factors for C-H bend (see main text and Appendix A). The final shifted band in the [10.0 - 15.3 µm] domain is represented in plain lines. The emission spectra from the Orion bar H2S1(Van Diedenhoven et al. 2004) and from the SMP SMC 16 planetary nebula (García-Hernández et al. 2010) are added for comparison.