Effect of Oxygen in the Surface-Catalyzed Excitation of Nitrogen

The emission of the nitrogen first positive bands which follows the recombination of nitrogen atoms at certain surfaces (surface‐catalyzed excitation) requires the presence of a small amount of electrically discharged oxygen. We find that the oxygen interacts in the gas phase to produce the emitting ${\mathrm{N}}_2{\mathrm{(B}}^3{\Pi }_g)$ from the vibrationally excited ${\mathrm{N}}_2{\mathrm{(A}}^3{\Sigma }_u^{+})$ which had been formed by N‐atom recombination at the surface. This interaction is very rapid, with a rate coefficient estimated at 5 × 10⁻¹² cm³ sec⁻¹. The species of oxygen which is involved is most likely an excited molecule. These results imply that ${\mathrm{N}}_2{\mathrm{(A}}^3{\Sigma }_u^{+})$ can be formed in high concentrations by the surface‐catalyzed excitation of nitrogen, provided that care is taken to insure an oxygen‐free system.