High Resolution Electron Energy Loss

HREELS is a surface sensitive spectroscopic technique in which a monochromatic beam of electrons is used to probe a surface under ultrahigh vacuum.  Figure 1 shows an electron beam interacting with an adsorbed carbon monoxide molecule.  In this case, some of the electron beam's energy has been converted into vibrational motion of the carbon monoxide and will result in a characteristic loss peak in the HREEL Spectra. 

The Hemminger lab has undertaken HREELS experiments of hydrocarbons and acids on atmospherically important metal oxide surfaces including aluminum oxide.  Figure two shows a sample set of spectra depicting tolulene adsorption on gamma aluminum oxide.(Layman, 2004)

Determination of surface OH acidity from the formation of acid/base complexes on ultrathin films of gamma-Al2O3 on NiAl(100)
K. A. Layman and J. C. Hemminger
Journal of Catalysis 2004, 222(1), 207-213.
10.1016/j.jcat.2003.11.010