Dissociative Attachment of Electrons in Iodine. I. Microwave Determination of the Absolute Cross Section at 300°K

Abstract

Microwave techniques are used to study electron attachment to iodine molecules during the afterglow following a pulsed discharge in an iodine-helium mixture. The helium gas decreases the ambipolar diffusion loss of the electrons and assures that the electrons are in thermal equilibrium with the gas during the afterglow. It is shown that under the experimental conditions electron attachment is the dominant electron-loss process. The measured cross section for electron attachment to iodine at 300°K is ${\sigma }_a=3.9\mathrm{}\times {10}^{-16\mathrm{}}$ ${\mathrm{cm}}^2$.