Ion Motion in Dielectric Gases

Abstract

Dielectric gases are used in a wide variety of important applications such as gas insulation and semiconductor fabrication (Christophorou 2000). As important as their use is their abatement (Kiehlbauch 2001), since gases like SF6 or some perfluorocarbons are potent greenhouse gases. The above processes require that at some stage the gas be subjected to discharge conditions, which are nowadays optimized by previous modeling and process simulation, which in turn demand the knowledge of cross sections and/or swarm and transport data for the numerous physico-chemical processes occuring in the discharge. It is well known that the extent of the present quantitative knowledge on electron-molecule (atom) interactions with dielectric gases, like electron scattering, electron impact ionization and dissociation, and electron transport, by far overwhelms that on ion-molecule (atom) interactions, in the form of elastic and inelastic momentum transfer and reaction cross sections, coefficients of mobility, diffusion and reaction rates, to name only the most relevant quantities. There exist many cases in the literature where a researcher faces the problem of having only meagre, or even lacking, ion swarm or cross section data to provide a quantitative explanation to the phenomenon under study or simulation.