A study of electron interactions with silicon tetrafluoride: elastic scattering and vibrational excitation cross sections.

We report absolute differential cross sections for elastic electron scattering from SiF₄. The incident electron energy range is 1.5-200 eV, while the scattered electron angular range was from 15° to 150°. The absolute scale of the differential cross sections was set using the relative flow technique with helium as the reference species. Corresponding integral elastic and momentum transfer data have been derived from our differential measurements. As a part of this study, independent atom model calculations were also performed. Those computations were found to be in generally quite good accord with the experimental results at both the differential and integral levels. In addition, excitation function measurements at a scattering angle of 60? and in the energy range 1-14 eV for the ν₃ (d-stretch) and ν₄ (d-deformation) fundamental vibrational modes are reported. Finally, differential cross sections for all four fundamental modes (ν₁, ν₂, ν₃, ν₄) at the single electron energy of 7 eV are given. These vibrational excitation measurements, when coupled with the elastic angular distributions in the 5-8 eV energy range, demonstrate the presence of a t₂-symmetry shape resonance. [ABSTRACT FROM AUTHOR]