Improvement of two-photon laser induced fluorescence measurements of H- and O-atoms in premixed methane/air flames

Abstract

photodissociation is shown to be an important photolytic source of H atoms in the reaction zone of the methane flames. At 226 nm, an efficient energy transfer between O(³P) and N₂ is established from the observation of O-resonant emissions from the second positive system of N₂. The subsequent rate of O(³P) depletion appears to be essentially “controlled” by the O(³P) concentration and is probably only minimally temperature dependent. Finally quenching rate coefficients for O(³P) by water and nitrogen are deduced from quenching rates measurements performed in CH₄/O₂/N₂ and CH₄/O₂/Ar flames.