Electron Drift Velocities and Electron Attachment Coefficients in Pure CHF₃ and its Mixtures with Argon

Abstract

Measurements are reported of (i) the electron drift velocity in pure trifluoromethane (CHF₃) gas and in its mixtures with argon, and (ii) electron attachment in pure CHF₃. the electric field-to-gas density ratio (E/N) dependence of the electron drift velocity in the mixtures exhibits regions of distinct negative differential conductivity. the values of the electron attachment coefficients in pure CHF₃ are small and decrease with E/N. the measurements were made at room temperature and cover the E/N range from 0.05 x 10^-17 V cm² to 60 x 10^-17V cm² (0.05 Td to 60 Td, 1 Td = 10^-17 V cm²). the electron attachment rate constant is virtually independent of E/N below about 50 x 10¹⁷ V cm² and equal to ∼ 13 x 10-¹⁴ cm³ s^-1. This small attachment rate constant may be due to impurities.