Fotóelektronspektroszkópia

Fotóelektronspektroszkópia, also known as photoelectron spectroscopy (PES), is an analytical technique used to determine the elemental composition and chemical state of a material. It works by measuring the kinetic energy of electrons emitted from a sample when it is irradiated by photons. The most common excitation source is ultraviolet (UV) light, leading to ultraviolet photoelectron spectroscopy (UPS), or X-ray radiation, resulting in X-ray photoelectron spectroscopy (XPS).

When a photon with sufficient energy strikes an atom in the sample, it can eject an electron. The energy of this emitted electron is related to the binding energy of the electron in the atom and the energy of the incident photon. By analyzing the distribution of kinetic energies of these emitted electrons, information about the electronic structure of the material can be obtained. Different elements have unique electron binding energies, allowing for their identification. Furthermore, subtle shifts in these binding energies can reveal the chemical environment or oxidation state of the atoms, providing valuable insights into chemical bonding and composition.

PES is a surface-sensitive technique, as the emitted electrons can only travel a short distance before being inelastically scattered. This makes it particularly useful for studying the surfaces of solids, thin films, and interfaces. Applications of PES span various fields, including materials science, chemistry, physics, and biology, aiding in the characterization of catalysts, semiconductors, polymers, and biological molecules.