Electron capture by haloethanes in a carbon dioxide buffer gas

An electron swarm method for investigation of the electron capture reaction has been modified. It is based on the registration of the temporal evoluti on of a single electron pulse. The method gives straightforward results on electron drift velocities in any mixture and allows calculating the rate co nstants for the electron capture. The thermal electron capture kinetics for eight haloethanes has been investigated. Only two-body attachment processe s have been found in their mixtures with carbon dioxide. All corresponding rate constants have been determined. A link between the two-body rate const ant and an electron polarizability of the attaching center has been demonst rated. (C) 2001 Elsevier Science B.V.