Infra-red Chemiluminescence from the Reactions of Atomic Hydrogen at Low Pressures

Abstract

WE have been attempting in this laboratory to extend previous observations of infra-red chemiluminescence^1–3 in the direction of lower pressures and faster flows. It was hoped that it might prove possible to eliminate secondary energy-transfer processes which were troublesome at higher pressures, and to observe more nearly the initial distribution of reaction product among vibrational states. To this end a large reaction vessel (about 10 litres) with four Wood's discharge tubes, and with multiple reflexion optics, has been developed; the apparatus has been described⁴ in connexion with an investigation of the system H + O₂. We wish to report here the first results on the systems H + Cl₂ and H + NOCl, examined in the same apparatus at total pressures of about 10⁻² mm. mercury.