Knowledge Base

The Photoelectic Effect

The fundamental principle behind the XPS process is the existence of the so-called ‘photoelectric effect’, which describes the interaction between matter and radiation pertaining to the electrons within the target atom. Essentially, when radiation with enough energy interacts with an atom, it may remove an electron (emitted electron is called a photoelectron) which will be released with a given kinetic energy. This kinetic energy is related to that of the incoming radiation, the binding energy of the electron within the atom and a small energy penalty for electron removal, which is called the work function of the spectrometer (Φ_sp).

E_k = hv – E_B – Φ_sp

Since the properties of hv and Φ_sp are known, and that of E_k measured – modern spectrometers typically automatically derive the binding energy of a measurement and display the results according to this value.