Mass Spectrometric Study of Positive Ion-Molecule Reactions in the C_3H_6 and Ar Mixtures Inside the High Pressure Ion Source

摘要

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_2H_2~+ (m/q = 26), C_2H_3~+ (m/q = 27), C_2H_4~+ (m/q = 28), C_2H_5~+ (m/q = 29), C_3H_3~+/~(39)Ar~+ (m/q = 39), C_3H_4~+/~(40)Ar~+ (m/q = 40), C_3H_5~+ (m/q = 41), C_3H_6~+/~(42)Ar+ (m/q = 42), C_3H_7~+ (m/q = 43), C_3H_8~+ (m/q = 44), C_4H_5~+ (m/q = 53), C_4H_6~+ (m/q = 54), C_4H_7~+ (m/q = 55), C_4H_8~+ (m/q = 56), C_4H_9~+ (m/q = 57), C_5H_5~+ (m/q = 65), C_5H_6~+ (m/q = 66), C_5H_7~+ (m/q = 67), C_5H_8~+ (m/q = 68), C_5H_9~+ (m/q = 69), C_5H_(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.