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

Abstract

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.