Type of spectroscopy involving the measurement of the kinetic energy of electrons emitted by chemical substances usually as a result of excitation by monochromatic X-rays.
Source:
PAC, 1976, 45, 221. 'Nomenclature and Spectral Presentation in Electron Spectroscopy Resulting from Excitation by Photons' on page 223 (https://doi.org/10.1351/pac197645030221)