Drift Velocities and Interactions of Negative Ions in Oxygen. II.O4−

Abstract

Drift velocities and reactions of negative ions have been investigated in oxygen at temperatures between 310 and 370 \ifmmode^\circ\else\textdegree\fi{}K at values of $\frac{E}{N}$ (the ratio of electric field to neutral-gas number density) between 2 and 400 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}17}$ V ${\mathrm{cm}}^{2}$, and at pressures (${P}_{0}$) between 0.5 and 4 Torr. Electrons were produced from a hot filament and reacted with the neutral-gas molecules to produce ions. The ions were then gated into a drift cell through a double grid, withdrawn through an aperture, and their mass and intensity were determined as a function of drift time by a quadrupole mass analyzer and a gated particle multiplier. Comparison of experimental results with numerical calculations allowed the determination of ion drift times and reaction rates. The rate constant for the reaction ${\mathrm{O}}^{\ensuremath{-}}+{\mathrm{O}}_{2}+{\mathrm{O}}_{2}\ensuremath{\rightarrow}{\mathrm{O}}_{3}^{\ensuremath{-}}+{\mathrm{O}}_{2}$ was found to be 9 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}31}$ ${\mathrm{cm}}^{6}$/sec at low $\frac{E}{N} (l30\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}17} \mathrm{V} {\mathrm{cm}}^{2})$. At higher $\frac{E}{N} (g70\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}17} \mathrm{V} {\mathrm{cm}}^{2})$ the reaction ${\mathrm{O}}^{\ensuremath{-}}+{\mathrm{O}}_{2}\ensuremath{\rightarrow}{\mathrm{O}}_{2}^{\ensuremath{-}}+\mathrm{O}$ was observed with a rate that increased sharply with $\frac{E}{N}$ to a value of 5 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}11}$ ${\mathrm{cm}}^{3}$/sec at $\frac{E}{N}=300\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}17}$ V ${\mathrm{cm}}^{2}$.