Low pressure flame determinations of rate constants for OH(A) and CH(A) chemiluminescence

Absolute excited state concentrations of OH(A), CH(A,B), and C-2(d) were determined in three low pressure premixed methane-air flames. Two-dimensional images of chemiluminescence from these states were recorded by a filtered CCD camera, processed by Abel inversion, and calibrated against Rayleigh scattering. Using a previously validated 1-D flame model with known chemistry and excited state quenching rate constants, rate constants are extracted for the reactions CH + O-2 --> OH(A) + CO and C2H + O --> CH(A,B) + CO at flame temperatures. Variations of flame emission intensities with stoichiometry agree well with model predictions. (C) 2002 by The Combustion Institute.