Interpretation of collisional ionization rates in flames

Abstract

This paper discusses semi-quantitatively the ionization process, A + M*→ A⁺+ e^–+ M*′, where A is an atom and M* and M*′ are differently excited states of a molecule. This process is particularly relevant to the discussion of the collisional ionization rates in flame systems, and estimates of the cross-sections for such processes together with a correct treatment of the number of states involved can readily account for the anomalously high cross-sections for such processes previously inferred from ionization rate constants. The discussion raises other related problems which suggest that a complete understanding of the process will not be readily obtained until more complex experiments correlating flame composition, ionization rates, electron densities and temperature variations are performed.