Valerie Coustet

High-resolution electron-energy-loss spectroscopy of isolated hydroxyl groups on α-Al2O3(0001)

Abstract Hydroxylated (0001) faces of α-Al 2 O 3 bulk crystals have been examined by high-resolution electron-energy loss spectroscopy (HREELS). Surface charging being eliminated by means of a defocused electron beam, it is shown that the electron fluence can be low enough to avoid significant damages. A resonance scattering from chemisorbed OH groups is evidenced, at impact energies lower than 12 eV, by strong enhancements of the cross sections for excitation of both the fundamental (3720 cm −1 ) and the first overtone (7270 cm −1 ) of the stretching mode and by the angular distribution of the inelastically scattered electrons.