In electron spectroscopy, depending on the technique, irradiating the sample with high-energy particles such as X-ray photons, electron beam electrons, or ultraviolet radiation photons, causes Auger electrons and photoelectrons to be emitted. Figure 1 illustrates this on the basis of a single particle in which, for example, the incoming X-ray photon from a particular energy range (E=hν) transfers its energy to an electron in the inner shell of an atom. Photon absorption caused electron emission leaves a hole in the atomic shell (see figure 1 (a)). The hole can be filled in two ways, forming different characteristic rays that are specific to each element. As the electron in the shell of a higher energy level fills the hole, a fluorescent photon is emitted (figure 1 (b)). In the Auger phenomenon, the electron in the shell of the higher energy level fills the hole that causes the adjacent or nearby electron to emit, forming the Auger electron (figure 1 (c)).
As can be seen from discussed above and figure 1, Auger electrons and photoelectrons are different in their physical origin, however, both types of electrons carry similar information about the chemical elements in material surfaces. Each element has its own special Auger electron or photon electron energy from which these can be identified. The binding energy of a photoelectron can be calculated by the formula below.
where E is the binding energy of the photoelectron, hν is the energy of the incoming radiation particle, E is the kinetic energy of the photoelectron measured by the device and  is the work function.
The kinetic energy of the Auger electron is approximately equal to the energy difference between the binding energies of the electron shells involved in the Auger process. This can be calculated as follows:
where E  is the kinetic energy of the Auger electron, hν is the energy of the incoming radiation particle and E is first outer shell binding energy and E  is second outer shell binding energies.