Core-loss EELS

It is now possible to create an atom sized electron beam that can probe the electronic structure of materials on the scale. Electrons passed through an electron spectrometer from such a probe give energy loss spectra that can provide insight on the local chemistry, bonding and electronic structure. In particular, electrons excited from core electron states explore the unoccupied states in the immediate vicinity of the atom. Such observations are particularly valuable in understanding chemical bonding in grain boundaries, heterointerfaces and chemically inhomogeneous regions of materials.