Mobility of CO+, CO2+ and C2O2+ Ions in Carbon Monoxide Gas

The mobilities of CO+, CO2+, and C2O2+ ions in carbon monoxide gas have been measured as a function of E / p0 (E is the electric field intensity, p0 is the normalized pressure) using the “four-gauze” electrical shutter device with a glow discharge ion source. Measurements were made at 29°–32°C gas temperature over a range of E / p0 from 15 to 180 V/cm·torr and in a pressure range of from 0.5 to 1.4 torr. The ions have been identified mass spectrometrically simultaneously with the measurement of their mobility. At p0 = 0.8 torr and E / p0 below 85 the predominant ion was found to be C2O2+ and at E / p0 above 85 the predominant ions were CO2+ and CO+. In addition, O2+, C3O2+, C4O2+ and C5O2+ ions in considerably smaller abundance have been observed. The mobility, extrapolated to zero field and atmospheric pressure, is 1.93 cm2/V·sec for both CO+ and CO2+ ions and 1.61 cm2/V·sec for C2O2+ ions. The binding energy of the C2O2+ ion against dissociation into CO+ and CO was found to be about 0.8 eV. Formation of the ions is discussed.