Detection of fluorocarbon intermediates in low-pressure premixed flames by laser-induced fluorescence

Laser-induced fluorescence (LIF) detection of CF, CHF, and CF2 is demonstrated in 10 Torr premixed methane/oxygen flames inhibited with CH3F, CH2F2, and CHF3. We discuss here the detection schemes required and present excitation spectra of CF and CHF. In these flames CF2 is a major source of spectral interference. LIF detection of carbonyl fluoride is also investigated. Less than 10% of the F atoms in the flames studied exit the reaction zone as CF2O, based on comparison with low-pressure C2F4/O2 flames.