Electron attachment and ionization processes in CF4, C2F6, C3F8, and n-C4F1

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Abstract
Measurements are reported of the electron attachment (ηT/N) and ionization (αT/N) coefficients for the perfluoroalkanes n‐CNF2N+2 (N=1 to 4) over the density‐reduced electric field (E/N) range 5×10−17≤E/N≤400×10−17 V cm2 using pulsed Townsend (PT) experimental techniques. The present ηT/N measurements are the first to be obtained for pure C2F6, C3F8, and n‐C4F10 at low E/N values. The ηT/N measurements in C3F8 and n‐C4F10 are dependent on gas pressure over a wide E/N range in agreement with previous high pressure electron attachment rate constant ka measurements in these gases. The dissociative and nondissociative electron attachment processes for C3F8 and n‐C4F10 have been quantified from the pressure dependence of the measured electron attachment coefficients ηT/N as a function of E/N. The thermal electron attachment rate constants (ka)th and the high voltage limiting electric field strengths (E/N)lim obtained from the present measurements are in good agreement with previous literature values.