Diffusion of Slow Electrons in Gases

Abstract

The diffusion of slow electrons in hydrogen, nitrogen, carbon dioxide, methane, ethylene, and cyclopropane in uniform electric fields has been investigated for ratios of electric field to pressure from 0.2 to 5.0 (v/cm)/mm Hg. Such measurements lead to a determination of the ratio of electron drift velocity to diffusion coefficient. By assuming a distribution in velocity of the electrons in the swarm, the Townsend energy factor $k_T$ and the mean electron velocity can be computed as a function of $\frac{E}{P}$, where $E$ is the electric field and $P$ is the gas pressure. Where the electron drift velocity is also known, the mean free path at unit pressure, the average energy loss per collision, and the gas kinetic cross section can be calculated. The results are presented in tabular form.