Reflected Electron Energy Loss Spectroscopy (REELS)

Reflected electron energy loss spectroscopy (REELS) is a technique used to probe the electronic structure of the material at the surface. In REELS, the incident particles are electrons, which can lose energy by causing electronic transitions in the sample. The reduced energy of the scattered electron beam is then measured and can provide information on properties such as electronic band gaps or the relative energy levels of unoccupied molecular orbitals. In some cases, it is also able to detect hydrogen, which is not possible with XPS.