Measurement of electron attachment processes in a high-temperature plasma

An experimental technique has been developed for measuring rate constants of electron attaching reactions as well as ion-molecule reactions in plasma at 2000-3000°K. Reaction product ions are mass analyzed and rate constants are obtained from plots of the collected ion current. The rate constant for O^-formation from N2O varies from about 3 to 9×10^-9cm³/s over the temperature range of 2400-3000°K while the rate constant for F^-formation from SF6varies from 2.8 to 4×10^-10cm³/s for temperatures from 2775 to 3000°K. A brief survey of experimental techniques for measuring electron attachment rate constants at lower temperatures is also given, together with a comparison of these rate constants and present high-temperature values.