Electron interactions with CCl2F2

In this article, available information on the cross sections and rate coefficients for collisional interactions of dichlorodifluoromethane (CCl2F2) with electrons is critically evaluated and synthesized. This gas has many industrial uses and is of atmospheric and environmental interest. The CCl2F2 molecule fragments rather extensively under electron impact, principally via dissociative ionization and dissociative attachment; the latter process is temperature dependent. Information is presented and discussed on: (1) electron scattering processes [cross sections for total electron scattering, momentum transfer, differential elastic electron scattering, integral elastic electron scattering, and inelastic electron scattering for rotational and vibrational (direct and indirect) excitation]; (2) electron impact ionization (cross sections for total, partial, and double ionization and coefficients for electron impact ionization); (3) electron attachment (electron attachment cross sections and rate constants and their energy and temperature dependencies, electron attachment coefficients, dissociative attachment fragment anions, and negative ion states); (4) optical emission under electron impact, and (5) electron transport coefficients (electron drift velocity and ratio of transverse electron diffusion coefficient to electron mobility). Based upon the assessment of published experimental data, recommended values of various cross sections and rate coefficients are generated in graphical and tabular form. Areas where additional data are needed are identified, such as the measurement of the cross sections for momentum transfer and electron impact dissociation of CCl2F2 into neutral species. (C) 1997 American Institute of Physics and American Chemical Society.