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Figure 1: A schematic view of the experimental set-up that was used. The combustion chamber contains the flat burner, cooled by circulating water. The flame is horizontal and the flow (pre-mixed) is maintained at a constant pressure within the chamber, at about a few tens of mbar. The burner is movable along the horizontal axis. The quartz sampling cone (shown) allows species produced at a given distance from the burner to enter the copper thermalisation chamber. This chamber is placed in the deposition chamber, which is maintained at a pressure of about 10-2 mbar under the operating conditions. A window is then placed into the jet that is formed at the end of the thermalisation chamber, where the gas passes through the nozzle. |
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Figure 2: Infrared absorption spectra of three different samples of laboratory soot (see the text for details). The spectra have been continuum subtracted to enhance the spectral profiles, as in Peeters et al. (2002). The spectra are presented in four spectral regions, normalized by intensity, allowing us to emphasize the band shape and position evolution within the specific frequency region. The regions are chosen to match those used previously by Peeters et al. (2002). |
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Figure 3:
Evolution of the ``6.2 ![]() ![]() ![]() ![]() |
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Figure 4: A selection of three astronomical spectra illustrating the spectroscopic differences encountered in the three spectral classes A-C of the Aromatic Infrared Bands. The spectra have been continuum- subtracted to enhance the spectral profiles, as per Peeters et al. (2002). The same normalisation procedure was applied as in Fig. 2. |
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Figure 5:
Dependence of the CH stretching mode region profile as a function of the ``6.2 ![]() |
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