Evolution of the position of the defect band at about 8 μm versus that at about 6.2 μm. Black dots: experimental data extracted from a sample of soot. These belong to the same sample that was used in Pino et al. (2008) and only those exhibiting a clear defect band were chosen, as may be seen in samples 2 and 3. Red triangles: observational data extracted from a sample of astrophysical objects. The region of the different AIB classes for each bands are shown, as defined in Peeters et al. (2002).