Heat-pipe-oven reactor (HPOR): I. A new device for flame studies; photon yields in the reaction of Na with CCl4 and N2O

Abstract

A new device based on the heat‐pipe oven has been demonstrated to have a unique capability for studying reactions of metal atoms with oxidizers. This device allows spherical diffusion flame studies under known, uniform, and easily adjustable, metal atom concentration. low gas pumping rate, clean window operation, and minimized problems of reactive solid disposal. The reactor was used for the study of chemiluminescence of the reactions of sodium vapors with CCl₄, with N₂O, and with both CCl₄ and N₂O. The emission from these reactions in the range 2000–9000 Å was identified to be from various excited atomic levels of sodium and from excited C₂, mostly in the Swan bands. Even though the emission was very intense, especially in the case of Na+N₂O+CCl₄ (photon yields of about 10%), it was found that the Na excited‐state populations had a Boltzmann distribution corresponding to an electron temperature of 2260 °K. This suggests that the emission of sodium radiation from both the Na+CCl₄ and Na+CCl₄+N₂O flames results from V→E transfer from vibrational reservoir states. In the former case, the excitation mechanism must involve energy pooling of C₂^‡ with either C(¹D) or Na(3p) atoms, while in the latter case, CO^‡ contributes as well. Sodium resonance radiation from the Na+N₂O flame is believed to result from secondary reactions of oxygen atoms.