OPTICAL CHARACTERIZATION OF SOOT

The chemistry of fuel-rich hydrocarbon flames is extremely complex bec ause different types of high molecular mass structures are produced. I n fact, Polycyclic Aromatic Hydrocarbons (PAH) and submicronic turbost ratic graphitic-like particles (soot) are not the only products presen t but also partially aromatic polymers, gums, fullerenes and diamond-l ike particles may be formed during pyrolysis and rich combustion. In a ddition, the heavy fractions of liquid fuels like the asphaltenes or t he large polar-aromatic compounds pyrolyze to specific forms of solid carbon. The tight requirement of a high space-time resolution of the m easurements during the high temperature combustion privileges the opti cal and spectroscopic diagnostics. This contribution will shortly revi ew the main optical effects employed in this field namely absorption a nd fluorescence spectroscopy and elastic light scattering.