HREELS DETECTION OF RESONANCE ELECTRON-SCATTERING IN ORIENTED POLYTETRAFLUOROETHYLENE FILMS

Resonance electron scattering from surfaces of oriented polytetrafluor oethylene (PTFE) has been investigated using high-resolution electron energy loss spectroscopy (HREELS). Oriented samples were made by frict ion-deposition onto gold-coated silicon wafers. A resonance enhancemen t of the 730 cm(-1), Raman-active upsilon (C-C) stretch vibrational mo de was detected near 5 eV beam energy with width of about 2 eV. The ma ximum intensity occurs for parallel alignment of the scattering plane with respect to the polymer chain, while no resonance is detected for perpendicular alignment. Studies were made for both specular and off-s pecular geometries. The origin of the resonance can be attributed to n egative ion trapping into the (C-C) sigma orbital. We have also obtai ned high resolutions of about 40 cm(-1) for the first time in polymer systems.