Spectral interferences to Raman bands due to laser-induced fluorescence are examined in exhaust gases from an internal combustion engine operating on different fuels and fuel/air mixtures. A broadband fluorescence spectrum is observed in all cases, but the relative fluorescence intensity depends strongly on the particular engine operating condition. Elimination of the fluorescence background by various exhaust conditioning devices confirmed the fact that aerosols of hydrocarbons or other organic compounds are the principal source.
R. E. Setchell and D. P. Aeschliman, "Fluorescence Interferences in Raman Scattering from Combustion Products," Appl. Spectrosc. 31, 530-535 (1977)