| Abstract: | The Langmuir — probe measurements in a CF4 — glow discharge reveal a large number of negative ions (1010 cm?3) in the plasma between the planar C-electrodes. Under special conditions the density of them exceeds the electron density at several orders of magnitude and sustains a quasi — electron free plasma. The ratio depends on the residence time of the molecular gas in the discharge reactor. It is due to dissociative electron attachment to highly molecular gas components arising from the plasmachemical conversion of CF4. F? and CF3? are the most important negative ions. |
