Influence of Repeller Potential on Ion-Molecule Reactions in $H_2S$ and $CH_4$ Mixtures

Ion-molecule reactions initiated by electron impact in the hydrogen sulfide-methane mixtures have been studied by means of quadrupole mass spectrometer with a high-pressure ion source. The total gas pressure of investigated mixtures was changed from 0.7 to 33.3 Pa. Influence of repeller potential on ion-molecule reactions have been studied. The repeller potential was changed in the range 2-12 V. Measurements were performed for different concentrations of methane and hydrogen sulfide in the mixture (from 10% $H_2S$ + 90% $CH_4$ to 90% $H_2S$ + 10% $CH_4$ with 10% increment). The major ion-molecule reactions have been identified. The primary ions $C^{+},$ $CH^{+},$ $CH_2^{+},$ $CH_3^{+},$ $CH_4^{+},$ $S^{+},$ $HS^{+},$ $H_2S^{+}$ produced in gas by the electrons with the energy of 300 eV and secondary $CH_5^{+},$ $C_2H_5^{+},$ $H_3S^{+},$ $H_2^{34}S^{+},$ $H_3^{34}S^{+},$ $CHS^{+},$ $CH_3S^{+},$ $S_2^{+},$ $HS_2^{+},$ $H_2S_2^{+}$ and $H_3S_2^{+}$ from the ion-molecule reactions were observed. Relative intensities for primary and secondary ions are presented as a function of potential of repeller electrode and concentration of methane in the mixture.