Pulse radiolysis study of argon-nitrogen mixtures. Measurement of the rate constant of metastable argon de-excitation by nitrogen

Abstract

The postluminescence of ${\mathrm{N}}_2{\mathrm{(C\hspace{0.17em}}}^3{\Pi }_u{\mathrm{\to \; B\hspace{0.17em}}}^3{\Pi }_g)$ induced by the transfer of energy to nitrogen by ³P₂ metastable argon atoms obtained by the pulsed radiolysis of argon‐nitrogen mixtures has been studied spectrophoto‐electrically. The emission decay lifetime $\tau$ is controlled by the destruction of metastable argon atoms. The variation of $\text{1/τ}$ as a function of the argon or nitrogen pressure is used to determine the rate constants $k_{\text{1(}\mathrm{Ar*}+{\mathrm{N}}_2)}{\text{=3± 0.3 × 10}}^{\text{−11}}{\mathrm{cm}}^3{\sec }^{\text{−1}}$ and $k_{\text{2(}\mathrm{Ar*}\text{+2}\mathrm{Ar})}{\text{=6± 0.4 × 10}}^{\text{−33}}{\mathrm{cm}}^6{\sec }^{\text{−1}}$ . The general reaction process is discussed. The results obtained seem to show that the metastables are formed mainly from the dissociative recombination of ${\mathrm{Ar}}_2^{+}$ ions.