Influence of repeller potential on ion–molecule reactions in methane and carbon tetrafluoride mixtures

Investigations of ion–molecule reactions were performed for methane–carbon tetrafluoride mixtures of different compositions. Concentration of methane in these mixtures ranged from 10% to 90% (at 10% increment) and total mixture pressure was fixed at 13.3 Pa. Measurements were made using a quadrupole mass spectrometer with a high-pressure ion source. Primary ions CH4+, F+, CF+ and CF3+ were produced by electrons with energy of 300 eV. Secondary ions CH5+, C2H3+, C2H4+, C2H5+, C2H7+ and CF3+ were observed as the result of ion–molecule reactions.The influence of repeller potential on ion–molecule reactions efficiency was examined.