Apparatus for high-resolution vibrational electron energy-loss spectroscopy of solid surfaces

A high-resolution vibrational electron energy-loss spectrometer of 127°-cylindrical electrostatic deflection type has been constructed for surface studies. In the direct mode, an electron current at the collector entrance of 2.3×10−11 A is obtained with the energy spread (full width at half-maximum) of 60 cm−1 for electrons whose energy at the sample position is 5 eV. A ghost reduction slit is used to suppress spurious peaks due to the electron reflection from electrodes of the analyzer. Electron energy-loss spectroscopy can be combined in situ with low-energy electron diffraction, Auger electron spectroscopy, and thermal-desorption mass spectroscopy. Design and performance of the apparatus are reported. The vibrational spectrum of the Ni(110) (1×2)-H surface formed at room temperature is presented, and the location of hydrogen atoms on the surface is discussed.