electron energy loss spectroscopy extended electron energy loss fine structure spectroscopy Spectroscopy where a beam of electrons with a known, extended range of kinetic energies is reflected by a surface and the energy loss the electrons suffer upon reflection is measured. Measurements are taken from the absorption edge onset to several hundred eV above it. extended energy loss fine structure spectroscopy CHMO:0000368 EXELFS spectroscopy ELFS spectroscopy extended electron energy loss fine structure spectrometry EELFS extended energy loss fine structure spectrometry EXELFS spectrometry EXEELFS ELFS spectrometry