(electron energy loss spectroscopy)
A technique for studying adsorbates and their dissociation. A beam of electrons is reflected from a surface and the energy loss they suffer upon reflection is measured. This loss can be used to interpret the vibrational spectrum of the adsorbate. Very small amounts of adsorbate can be detected using EELS (as few as 50 atoms in a sample); this is particularly useful for light elements that are not readily detected using other techniques.