Mass Spectrometric Study of Positive Ion-Molecule Reactions in the $C_{3}H_{6}$ and Ar Mixtures Inside the High Pressure Ion Source

Ion-molecule reactions have been measured for the propene-argon mixtures of different compositions using a quadrupole mass spectrometer with a high-pressure ion source. The concentration of propane in these mixtures ranged from 10% to 90% (at 10% increment). The following primary and secondary ions: $CH_{5}^{+}$ (m/q=17), $C_{2}H_{2}^{+}$ (m/q=26), $C_{2}H_{3}^{+}$ (m/q=27), $C_{2}H_{4}^{+}$ (m/q=28), $C_{2}H_{5}^{+}$ (m/q=29), $C_{3}H_{3}^{+}//\text{}^{39}Ar^{+}$ (m/q=39), $C_{3}H_{4}^{+}//\text{}^{40}Ar^{+}$ (m/q=40), $C_{3}H_{5}^{+}$ (m/q=41), $C_{3}H_{6}^{+}//\text{}^{42}Ar^{+}$ (m/q=42), $C_{3}H_{7}^{+}$ (m/q=43), $C_{3}H_{8}^{+}$ (m/q=44), $C_{4}H_{5}^{+}$ (m/q=53), $C_{4}H_{6}^{+}$ (m/q=54), $C_{4}H_{7}^{+}$ (m/q=55), $C_{4}H_{8}^{+}$ (m/q=56), $C_{4}H_{9}^{+}$ (m/q=57), $C_{5}H_{5}^{+}$ (m/q=65), $C_{5}H_{6}^{+}$ (m/q=66), $C_{5}H_{7}^{+}$ (m/q=67), $C_{5}H_{8}^{+}$ (m/q=68), $C_{5}H_{9}^{+}$ (m/q=69), $C_{5}H_{10}^{+}$ (m/q=70) were observed. Relative ion current intensities for primary and secondary ions are presented as a function of both total mixtures pressure and concentration of propene in the mixture. Primary ions were produced by electrons with the energy of 300 eV. The potential of repeller electrode $V_{R}$ inside the ion source collision chamber was fixed at 5 V for all measurements. The total mixture pressure was changed from 0.7 to 26.6 Pa. Schemes of ion-molecule reactions were proposed.