Spectra of flames supported by free atoms

Abstract

The spectra of the ‘atomic flames’ of organic compounds with the products of discharges through oxygen, hydrogen and water vapour have been examined. Hydrocarbons give bright flames with water products but not, contrary to previous reports, with dry atomic hydrogen. Carbon tetrachloride and other organic halides and also carbon disulphide do give bright flames with hydrogen. The rotational intensity distribution in the OH band in most atomic flames corresponds to a very high temperature, around 8000° K; it is high for methyl alcohol with water products, but only around 2500° K for methyl alcohol with atomic oxygen. The flame of acetylene with products from heavy water, D 2 O, gives mainly OD and CD rather than OH and CH bands. The mechanism of formation and excitation of CH and OH in flames is discussed. When iron carbonyl is introduced into atomic flames very high electronic excitation of iron atoms is observed, as in the reaction zones of ordinary premixed flames; this high excitation is also observed for the flame of carbon tetrachloride with atomic hydrogen.