Determination of Collisional Quenching Rate Coefficient of N$_2$(A$^3\Sigma_u^+)$ by H$_2$O

The effective lifetimes of metastable excited molecule N$_2$(A$^3 \Sigma_u^+$) in N$_2$/10.2ppm H$_2$O and N$_2$/103ppm H$_2$O mixtures were measured by waveform analysis$^{(1)}$ of the transient ionization current after interruption of the initial electron from the cathode in the Townsend discharge region. The collisional quenching rate coefficient of N$_2$(A$^3 \Sigma_u^+$) by H$_2$O was determined together with the diffusion coefficient of N$_2$(A$^3 \Sigma_u^+$) in nitrogen and the reflection coefficient of N$_2$(A$^3\Sigma_u^+$) at the cathode surface with the procedure based on the diffiusion equation analysis$^{(2)}$. The obtained collisional quenching rate coefficient of N$_2$(A$^3 \Sigma_u^+$) by H$_2$O is 5.7$\times$10$^{-13}$ cm$^3$/s. This value is ten times as large of the value reported by Callear and Wood$^{(3)}$. (1) S. Suzuki, H. Itoh, H. Sekizawa and N. Ikuta, J. Phys. Soc. Jpn., 62, No.8, 2692-2697 (1992) (2) S.Suzuki and H.Itoh, J. Phys D: Appl. Phys., 49,185202(14pp) (2016) (3) A. B. Callear and P. M. Wood, Trans. Faraday Soc., 67, 598-600 (1971)