Effect of halogens on the ionization in alkali-laden hydrogen and acetylene flames. Part 2.—Results and derived rate constants

Abstract

Observations are reported on the change in electron concentration in the burnt gases of hydrogen + oxygen+nitrogen flames containing small amounts of acetylene and controlled traces of alkali elements when amounts of halogens up to ca. 1 % are added. In many cases the electron concentration passes through a pronounced maximum. The results are interpreted in terms of a mechanism advanced previously,¹ the essential point of which is that whereas alkali atoms A are ionized by collisional processes with third bodies X in the absence of halogen, A+X⇌A⁺+e^–+X, the presence of halogen allows an electron exchange mechanism A+B⇌A⁺+B^– to operate, B representing an atom of halogen. Rate constants are deduced for the reaction of A⁺ with B^–, and compare reasonably with theoretical estimates.