High pressure mass-spectrometric investigations of ion-molecule reactions in propane and argon mixtures

Ion-molecule reactions initiated by electron impact in the propane-argon mixtures have been studied by a quadrupole mass spectrometer with a high pressure ion source. The total gas pressure of investigated mixtures was 1.33 Pa. The influence of repeller potential on the ion-molecule reactions has been studied. The repeller potential was changed in the range 2-12 V. Measurements were performed for different concentrations of propane in the mixture with argon (from 10% C3H8 + 90% Ar to 90% C3H8 + 10% Ar with 10% propane increments). The major ion-molecule reactions have been identified. The primary ions produced in the gas by the electrons with the energy of 300 eV and the secondary ones from the ion-molecule reactions were observed. Relative intensities for primary and secondary ions are presented as a function of potential of the repeller electrode and concentration of propane in the mixtures with argon.