Vibrational effects on electron-impact valence excitations of SF6

We report an angle-resolved electron-energy-loss spectroscopy study on the valence excitations of SF6. Momentum-transfer-dependent generalized oscillator strengths (GOSs) or GOS profiles of the low-lying valence excitations have been derived from electron-energy-loss spectra measured at an incident electron energy of 3 keV. We have also performed theoretical calculations of the GOS profiles involving the influence of molecular vibration. Comparisons between experiment and theory have revealed that coupling between electronic states through molecular vibration plays a significant role in the 1 T-1(1g) dipole-forbidden transition.