Reactions of Metastable Nitrogen Atoms

Abstract

The line absorption technique was applied to the kinetic study of the two metastable atomic nitrogen states N (2²D) and N (2²P) in a flowing afterglow system. The optical absorptions of the N_I 1493‐Å ${\text{(2p}}^{32}{\text{D−3s}}^2\mathrm{P)}$ and 1743‐Å ${\text{(2p}}^{32}{\text{D−3s}}^2\mathrm{P)}$ transitions were used for the quantitative measurement of N (2²D) and N (2²P) concentrations. Deactivation of N (²D) and N (²P) by the Pyrex tube wall was found to be very efficient, i.e., occurs at nearly every collision. The second‐order rate constants at 300°K for the removal of N (²D) by O₂, N₂O, CO₂, NO, N₂, Ar, and He were found to be ${\text{(6±2)×10}}^{\text{−12}}{\text{,\hspace{0.17em}(3.5±1.2)×10}}^{\text{−12}}{\text{,\hspace{0.17em}(5±2)×10}}^{\text{−13}}{\text{,\hspace{0.17em}(7±2.5)×10}}^{\text{−11}}{\text{,\hspace{0.17em}(1.6±0.7)×10}}^{\text{−14}}{\text{,\hspace{0.17em}(1±0.6)×10}}^{\text{−16}}$ , and ${\text{≤ 1.6×10}}^{\text{−16}}\hspace{0.17em}{\mathrm{cm}}^3\hspace{0.17em}{\sec }^{\text{−1}}$ , respectively. It was established that the process for the first three reactant gases results in chemical reaction rather than physical quenching.