Electron attachment and ionization processes in CF₄, C ₂F₆, C₃F₈, and n-C₄F ₁₀

Measurements are reported of the electron attachment (η_T/N) and ionization (α_T/N) coefficients for the perfluoroalkanes n-C_NF_2N+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 η_T/N measurements are the first to be obtained for pure C ₂F₆, C₃F₈, and n-C₄F ₁₀ at low E/N values. The η_T/N measurements in C ₃F₈ and n-C₄F₁₀ are dependent on gas pressure over a wide E/N range in agreement with previous high pressure electron attachment rate constant k_a measurements in these gases. The dissociative and nondissociative electron attachment processes for C ₃F₈ and n-C₄F₁₀ have been quantified from the pressure dependence of the measured electron attachment coefficients η_T/N as a function of E/N. The thermal electron attachment rate constants (k_a)_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.