Identification of a source of argon-ion-laser excited fluorescence in sooting flames

Combustion-formed nanoparticles

“…Light sources in the UV can also induce electronic transitions and subsequent emission of fluorescence in specific classes of molecules such as polycyclic aromatic hydrocarbons (PAH) and oxygen-containing compounds [36][37][38][39][40][41][42][43]. For nanoparticles, exhibiting molecular characteristics, Laser Induced Fluorescence (LIF) may also be a useful detection tool [44][45][46].…”

Temperature Measurements in High Pressure Combustion

“…It was assumed that Ydeph is independent of temperature and rotational quantum state. Under this assumption, Rahn et al [33] determined a value of 0.6.10-3 cm-' bar-' for ydeph. The theoretical work Of Robert [36,371 and measurements by Smyth [38] in 0 2 collision systems indicate a strong increase of the vibrational dephasing contribution by foreign gas collisions.…”

“…However, for H2 thermometry in a flame the situation is more complex, because the different collision partners present in the varying chemical environment will definitively change the interaction potential compared to pure H2 -H2 collisions. Due to the very limited experimental and theoretical knowledge of the various line broadening processes of H2 Q-branch lines caused by the influence of foreign gas molecules, we tried an extrapolation of the rotation-translation energy transfer rates t o flame temperatures using the ECS scaling law and the fit parameters given by Rahn et al [33]. The required basis rates for H2-H2 collisions were calculated according to…”

“…The results of ECS calculations have been plotted in Fig. 9 together with the data of Rahn et al [33], the contribution of vibrational dephasing to the pressure broadening coefficients. It was assumed that Ydeph is independent of temperature and rotational quantum state.…”

Aromatic excimers: evidence for polynuclear aromatic hydrocarbon condensation in flames

“…In the ensuing years, scores of papers have been written that report both visible and ultraviolet emissions, and that have attempted to unambiguously assign the fluorescing species [5,[8][9][10][11][12][13][14]. This rich literature has been reviewed in two recent contributions and will only be summarized briefly below [15,16].…”