Townsend energy coefficients for electron swarms in polyatomic gases

Abstract

Townsend's energy coefficient k has been measured as a function of E/P for electrons in CH₄, CD₄, SiH₄, SiD₄, C₂H₆, C₃H₈ and CH₃OCH₃. The results are used in conjunction with previously determined electron drift velocities to evaluate Q_D, the electron/molecule momentum transfer cross-section, and λ, the fractional energy lost by an electron in a collision with a gas molecule. These are discussed in terms of low energy resonances between electrons and molecules.