Spectroscopic characterization of the fluorobenzene/DEMA tracer system for laser-induced exciplex fluorescence for the quantitative study of evaporating fuel sprays

• Published in: Applied physics. B, Lasers and optics Vol. 97; no. 4; pp. 909 - 918
• Main Authors: Düwel, I., Koban, W., Zimmermann, F. P., Dreier, T., Schulz, C.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.12.2009; Springer
• Subjects: Atomic and molecular physics; Atomic properties and interactions with photons; Biological and medical applications; Cross talk; Engineering; Exact sciences and technology; Fluorescence; Fluorescence, phosphorescence (including quenching); Fuel sprays; Fundamental areas of phenomenology (including applications); Lasers; Liquids; Molecular properties and interactions with photons; Molecular spectra; Monomers; Optical Devices; Optics; Photonics; Physical Chemistry; Physics; Physics and Astronomy; Quantitative analysis; Quantum Optics; Temperature dependence; Vapor phases; 42.62.-b; 32.50.+2; 33.20.-t; Temperature dependence; Amines; Vapor phase; Laser induced fluorescence; Hexane; Gas phase; Liquid phase; Laser beam applications; Nitrogen; Fuels
• ISSN: 0946-2171; 1432-0649
• DOI: 10.1007/s00340-009-3652-3

Quantitative analysis of laser-induced exciplex fluorescence (LIEF) requires knowledge of the spectral characteristics of all the involved substances. The temperature dependence of the ratio of exciplex and monomer in the liquid phase as well as the temperature-dependent fluorescence intensity from monomers in the gas phase must be known when quantifying signals and correcting for cross talk between liquid and vapor phase. In this work we present an extensive characterization of the fluorescence of the fluorobenzene/diethyl-methyl-amine (DEMA)/n-hexane exciplex system. We use a mixture of 2% fluorobenzene, 9% DEMA, and 89% n-hexane, which was tested before for its coevaporative behavior. The temperature dependent fluorescence of the liquid exciplex was studied in a thin layer cell with UV-light (266 nm) excitation. Cross talk of a known combination of bandpass filters was quantified for the relevant temperature range. The temperature dependence of the gas-phase absorption and fluorescence signal (fluorobenzene) was studied in a heated static cell and a heated gas stream in a nitrogen coflow, respectively. These measurements provide the background for the application of LIEF for quantitative analysis of vapor and liquid distributions in fuel sprays.