Applications of surface vibrational spectroscopic techniques
An advanced Electron Energy Loss Spectrometer has been used to study the formation of 3,3,3-trifluoropropylidyne on Pt (111). This has been compared to the results from the same system using the complementary vibrational spectroscopic technique of Reflection Absorption Infrared Spectroscopy (RAIRS). This study demonstrates the improved resolution of the new spectrometer. The thermal decomposition products, CF3 and CF2 have been detected in the Electron Energy Loss (EEL) spectra. The RAIR spectra of carbon monoxide on Cu (111) have been recorded using synchrotron radiation. An optical accessory has been used to record the RAIR spectra at an incident angle of 20°. The results have been compared to an incident angle of 87°. At 20° no conventional absorption band at 339 cm-l was observed and an anti absorption band at 274 em-l of similar magnitude to that at 87° was seen. This has confirmed the involvement of the parallel electric field in the observation of antiabsorption bands. The EEL spectra of hydrogen and deuterium adsorbed on Pt (111) at 160 K have been recorded. The data has been interpreted using the Nearest Neighbour Central Force Constant (NNCFC) model in terms of 3- fold and 2-fold bridging sites. It is the 2-fold site which offers the more complete assignment of the vibrational bands observed.