Infrared spectra for the flakes and branched families and comparison with astronomical spectra. Panels a and b show a zoom into the [2.8–4 µm] region. Panels c and d show the features represented with dashed lines in the [10.2–22.7 µm] region 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. Error bars are reported in panels a and c for the most intense bands of the IR spectrum of C₂₄H₆ flakes only, but can be applied to similar modes for all stoichiometries and families.