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 ${\mathrm{E\hspace{0.17em}/\hspace{0.17em}p}}_0$ ($E$ is the electric field intensity, $p_0$ 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 ${\mathrm{E\hspace{0.17em}/\hspace{0.17em}p}}_0$ 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 $p_0\text{\hspace{0.17em}=\hspace{0.17em}0.8}\mathrm{torr}$ and ${\mathrm{E\hspace{0.17em}/\hspace{0.17em}p}}_0$ below 85 the predominant ion was found to be C₂O₂⁺ and at ${\mathrm{E\hspace{0.17em}/\hspace{0.17em}p}}_0$ 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.