Scattering cross sections and electron transport coefficients for electrons in CF<inf>3</inf>I

Abstract

Electron transport coefficients and rate coefficients in pure CF 3 I and its mixtures with Ar, Xe, N 2 and SF 6 have been calculated for a set of cross-sections which was based on the work of Kimura and Nakamura [1] but which was modified to improve agreement between the calculated swarm parameters and the experimental values. Electron drift velocity, effective ionization coefficient and diffusion coefficients are calculated using a Monte Carlo simulation technique and from solution of the non-conservative Boltzmann equation [2]. Calculated data for pure CF 3 I and its mixtures with Ar, Xe, N 2 and SF 6 are compared with those measured under both time-of-flight (TOF) and pulsed-Townsend (PT) conditions. We note the existence of negative differential conductivity (NDC) in the profile of the bulk drift velocity with no signs of the same phenomenon in the profile of flux drift velocity. We systematically study the origin and mechanisms for such phenomena as well as the possible physical implications which arise from their explicit inclusion into plasma models. Spatially-resolved electron transport properties are calculated using a Monte Carlo simulation technique in order to understand these phenomena. Special attention is paid upon the implementation of procedure for compensation of electrons for losses due to strong electron attachment in our Monte Carlo code.