Pressure and temperature dependence of dissociative and non-dissociative electron attachment to CF3: Experiments and kinetic modeling

Abstract

The kinetics of electron attachment to CF(3) as a function of temperature (300-600 K) and pressure (0.75-2.5 Torr) were studied by variable electron and neutral density attachment mass spectrometry exploiting dissociative electron attachment to CF(3)Br as a radical source. Attachment occurs through competing dissociative (CF(3) + e(-) → CF(2) + F(-)) and non-dissociative channels (CF(3) + e(-) → CF(3)(-)). The rate constant of the dissociative channel increases strongly with temperature, while that of the non-dissociative channel decreases. The rate constant of the non-dissociative channel increases strongly with pressure, while that of the dissociative channel shows little dependence. The total rate constant of electron attachment increases with temperature and with pressure. The system is analyzed by kinetic modeling in terms of statistical theory in order to understand its properties and to extrapolate to conditions beyond those accessible in the experiment.