Valence-shell angle-resolved electron energy loss spectra of SF6

Abstract

Electron-energy-loss spectra of the SF6 molecule have been measured in the valence-shell region (0 - 100 eV) covering an angular range of 1.0° - 15.0°. The spectra have been measured at an impact energy of 1.0 keV. The angular dependence of the spectra showed the presence of three forbidden transitions in the region below 40 eV. Above 40 eV interesting features appear at higher scattering angles, which can be associated to nondipole many-body processes. A new feature was observed at 76 eV. The absolute elastic differential cross section has been obtained through normalization of the relative data to the experimental values found in the literature. The absolute inelastic differential cross sections for the 11.5 eV and 13.2 eV transitions have been determined. The generalized oscillator strength (GOS) for the 11.5 eV peak has been also determined in the 0.05 to 1.3 a.u. K² range. The experimentally determined value for the optical oscillator strength(0.312) for the 11.5 eV peak obtained through extrapolation of the GOS curve showed good agreement with the data found in the literature.

Keywords

• sulphur hexafluoride
• electron energy loss spectroscopy
• forbidden transitions
• generalized oscillator strength