Electron Interactions With Cl2

Abstract

Low-energy electron interactions with the Cl2 molecule are reviewed. Information is synthesized and assessed on the cross sections for total electron scattering, total rotational excitation, total elastic electron scattering, momentum transfer, total vibrational excitation, electronic excitation, total dissociation into neutrals, total ionization, total electron attachment, and ion-pair formation. Similar data on the density-reduced ionization, density-reduced electron attachment, density-reduced effective ionization, electron transport coefficients, and electron attachment rate constant are also synthesized and critically evaluated. Cross sections are suggested for total electron scattering, total elastic electron scattering, total ionization, dissociation into neutrals, electron attachment, and ion-pair formation. A cross section is derived for the total vibrational excitation cross section via low-lying negative ion resonances. Data are suggested for the coefficients for electron attachment, ionization, and effective ionization, and for the rate constant for electron attachment. While progress has been made regarding our knowledge on electron–chlorine interactions at low energies (<100 eV), there is still a need for: (i) improvement in the uncertainties of all suggested cross sections; (ii) measurement of the cross sections for momentum transfer, vibrational excitation, electronic excitation, and dissociative ionization; and (iii) accurate measurement of the electron transport coefficients in pure Cl2 and in mixtures with rare gases. Also provided in this paper is pertinent information on the primary Cl2 discharge byproducts Cl2+, Cl2−, Cl, Cl−, and Cl+.