Electron impact single and double ionization and dissociation: revisiting CF4 and CHF3 with an improved experimental method

Abstract

The absolute total and partial ionization cross sections resulting from electron collisions with fluorinated molecules CF₄ and CHF₃ were obtained by recoil-ion momentum spectroscopy with full acceptance for energetic ionic fragments. For absolute normalization the relative-flow technique was applied. The cross sections for single and double ionization as well as for dissociation were measured for electron energies from 20 eV to 1 keV. The data are compared with previous experiments and model calculations. The dissociation channel specific differences between CF₄ and CHF₃ are discussed. The present data are relevant for the evaluation of the electron interaction on these potent greenhouse gases with a high global warming potential in the Earth biosphere and in plasma and other industrial applications.