This paper deals with the presentation and discussion of some recent measurements on the interaction of electron and ion swarms in gases, with particular emphasis on flourinated gases. The processes to be discussed are related to electron impact ionization and attachment, including Penning ionization and electron detachment. Electron transport is discussed in mixtures of SF₆ and fluorocarbon gases, where interesting regions of negative differential conductivity have been observed in C₂F₄, and apparent pressure dependences of the drift velocity in C₄F₈. Ion transport is discussed in terms of recent measurements on positive and negative ions in SF₆ and Ar. Finally, the subject of ion–molecule reactions is illustrated with the dissociation and charge transfer processes of daughter ions in nitrogen. Throughout the paper, the advantages and limitations of both the pulsed Townsend technique and the drift tube-mass spectrometer are highlighted.

52.20.Hv Atomic, molecular, ion, and heavy-particle collisions

52.25.Fi Transport properties

52.27.-h Basic studies of specific kinds of plasmas

52.25.Jm Ionization of plasmas

Plasma physics

Issue 3A (August 2002)

Received 26 September 2001 , in final form 17 April 2002

Published 19 August 2002