Chain reaction chemiluminescence of alkaline earth catalyzed N2O–CO flames

Abstract

The combustion of a dry N₂O–CO mixture was initiated upon mixing the gases with Mg, Ca, or Sr atoms entrained in a He carrier flow. The flames were supported in a low pressure, fast flow reactor and were marked by intense chemiluminescence corresponding to the metal atom ³P₁→¹S₀ transition and the well known molecular bands of the metal oxides. Additionally, bands in the visible and ultraviolet were observed. By comparison with the similar banded emissions obtained upon mixing active nitrogen with metal–N₂O and metal–H₂O flames, it was possible to distinguish the chemiluminescence obtained in the dry N₂O–CO flames from the nearly identical metal monohydroxide flame bands. The new bands are identical to those previously obtained in arcs and they are shown to correspond to transitions between excited triplet and singlet states of the diatomic metal oxides. Photon yield studies and intracavity resonant absorption measurements further indicate that these systems are prime candidates for development as a three level chemically driven electronic transition laser system.