Picosecond planar laser-induced fluorescence measurements of OH A 2 + ( ' = 2) lifetime and energy transfer in atmospheric pressure flames.

摘要: A picosecond, excimer-Raman laser (268 nm, 400 ps FWHM) was used for laser sheet excitation of OH in the (2, 0) band. The fluorescence detected with a fast-gated, intensified camera (400-ps gate width). effective collisional lifetime spectrally integrated measured in two dimensions by shifting intensifier across decay curve. The average is ∼2.0 ns for stoichiometric methane–air flame with spatial variations ±10%. Shorter collisional lifetimes were rich flame conditions that are due to higher number density quenchers. Vibrational energy transfer (VET) observed in premixed and methane–oxygen flames putting the fast-gated behind spectrometer. spectrum methane–air flame shows strong VET contrast with flame. This is because N2 weak electronic quencher but a strong agent. By fitting time dependence different vibrational populations (ν′ = 2, 1, four-level model, rate constants quenching were determined. For lower states (ν′ 0, 1) our results good agreement literature values. prediction integrated, a known environment it important consider not only the quenching also amount excited state as well as spectral detection sensitivity.