EN
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.