Determination of collisional quenching rate coefficient of $N_2 (A^3\Sigma _u^+ )$*

We have previously determined the collisional quenching rate coefficient of $N_2 (A^3\Sigma _u^+ )$ by an air pollutant gas [1-4]. In this paper we report the collisional quenching rate coefficient $k$' of $N_2 (A^3\Sigma _u^+ )$ by $p$-xylene (C$_{8}$H$_{10})$, which was determined to be (6.5$\pm$0.9)$\times$10$^{-9}$ cm$^{3}$/s. In addition, through repeated experiments it was found that by-products of $p$-xylene were deposited on the cathode, similarly to the cases of $m$-xylene and $o$-xylene previously reported [4], and then the current-voltage curves consistently shifed to a higher-$E$/$p_{0}$ region. To clarify the reason for this behavior, we confirmed by Auger electron spectroscopy (AES) and Fourier transform infrared spectroscopy (FTIR) that these changes in the current-voltage curves were caused by the deposition of a thin film of by-product of decomposed xylene on the cathode surface. According to the results of AES, C atoms were detected in a sample exposed to an electrical discharge, and we confirmed that the deposit of C was thickest in the case of electrical discharge in $p$-xylene. According to the results of FTIR, it was found that CH$_{2}$ and CH were obtained from the deposition of $p$-xylene. \\[4pt] [1] S. Suzuki, H. Itoh, H. Sekizawa and N. Ikuta, J. Phys. Soc. Jpn., 62, No.8, 2692-2697 (1993)\\[0pt] [2] S. Suzuki, H. Itoh, H. Sekizawa and N. Ikuta, Jpn. J. Appl. Phys., 36, 4744-4746 (1997)\\[0pt] [3] S. Suzuki, T. Suzuki and H. Itoh, Cont. of HAKONE X Saga, Japan, 132-135 (2006)\\[0pt] [4] S. Suzuki, H. Itoh, Proc. of 30th ICPIG (Belfast, UK), A1-12 (2011)