Energy transfer in combustion diagnostics: experiment and modeling.
Laser induced fluorescence (LIF) of OH (A 2 sigma +) is measured in several atmospheric-pressure flames using a short-pulse laser system (80 ps duration) in conjunction with an intensified streak camera. The two-dimensional signal-detection technique allows one to simultaneously monitor rotational and vibrational relaxation as well as electronic quenching. Rotationally-resolved LIF spectra affected by energy transfer are compared with the results of a rate-equation model and are found to be in reasonably good agreement. It is shown that a significant contribution of fluorescence detected by broad-band techniques is due to levels populated by vibrational energy transfer (VET). Implications for picosecond LIF techniques for the time-resolved, quench-free detection of OH are discussed. A detailed analysis is presented for fluorescence spectra originating from levels populated by VET after excitation of states in the OH (A 2 sigma +, v' = 2) level.
Brockhinke
A
A
Physikalische Chemie I, Fakultät für Chemie, Universität Bielefeld, Universitätsstr. 25, D-33615 Bielefield, Germany. brockhinke@pc1.uni-bielefeld.de
Kohse-Höinghaus
K
K