Determination of collisional quenching rate coefficients of metastable nitrogen molecules by air pollutants

It has already been investigated on the determination of the collisional quenching rate coefficients of the metastable nitrogen molecules $N_2 (A^3\Sigma _u^+ )$ by some air pollutants [1] in our laboratory. In this report, we present the result on the collisional quenching rate coefficient of $N_2 (A^3\Sigma _u^+ )$ by formaldehyde (CH$_{2}$O) using a theoretical procedure that takes into account the reflection of metastables at the boundary. As far as we know, this report is the first result of the collisional quenching rate coefficients of $N_2 (A^3\Sigma _u^+ )$ by CH$_{2}$O. Formaldehyde is a colorless gas with the foul odor, and elements of the adhesive, paints, and preservative, etc. It is widely used for construction materials such as houses, because it is low cost. It is released from paint of construction materials in air, and, in that case, it is known as one of the causative agents of so-called ``Sick building syndrome'' to influence the human body harmfully even if it is a low concentration. The obtained collisional quenching rate coefficient of $N_2 (A^3\Sigma _u^+ )$ by CH$_{2}$O is (4.7$\pm$0.4) $\times$ 10$^{-12}$ cm$^{3}$/s. Because the collisional quenching rate coefficient by CH$_{2}$O is large, it is understood that CH$_{2}$O receives energy easily from $N_2 (A^3\Sigma _u^+ )$. In addition, we reports on the obtained collisional quenching rate coefficient of $N_2 (A^3\Sigma _u^+ )$ by some air pollutants. [1] S. Suzuki, T.Suzuki and H.Itoh: Proc. of XXVIII ICPIG (Prague, Czech Republic), (2007) 1P01-40.