the main peaks occur at kinetic energies of ca. The diagram below shows a real XPS spectrum obtained from a Pd metal sample using Mg K α radiation \[A + hν \rightarrow A^+ + e^- \label\): The XPS spectrum of Pd metal The process of photoionization can be considered in several ways : one way is to look at the overall process as follows : the number of emitted photoelectrons as a function of their kinetic energy) can be measured using any appropriate electron energy analyzer and a photoelectron spectrum can thus be recorded. The kinetic energy distribution of the emitted photoelectrons (i.e. By contrast, in UPS the photon interacts with valence levels of the molecule or solid, leading to ionization by removal of one of these valence electrons. In XPS the photon is absorbed by an atom in a molecule or solid, leading to ionization and the emission of a core (inner shell) electron. Photoelectron spectroscopy uses monochromatic sources of radiation (i.e. \(\nu\) is th e frequency (Hz) of the radiation.The energy of a photon of all types of electromagnetic radiation is given by the Einstein relation :
Photoelectron spectroscopy is based upon a single photon in/electron out process and from many viewpoints this underlying process is a much simpler phenomenon than the Auger process.