Excitation of valence-band electrons in a solid in which collective oscillations are generated.
Notes: - Plasmon excitations are often observed as characteristic energy loss peaks associated with other peaks in the spectrum, such as those of any elastically scattered primary electrons, photoelectron peaks, Auger electron peaks, and ionization edges.
- Plasmons are prominent in some materials and not others.
- Two types of plasmon are commonly observed: bulk plasmons, associated with material remote from the surface, and surface plasmons, associated with material at the surface. When the term plasmon is used without a qualifier, the term refers to the bulk plasmon. Occasionally, interface plasmons can be observed that are associated with interfaces. Bulk plasmon energies depend on the electronic structure of the material and are roughly proportional to the square root of valence-band density. Surface plasmon energies are typically between \(\pu{50\%}\) and \(\pu{90\%}\) of bulk plasmon energies.
Source:
PAC, 2020, 92, 1781. 'Glossary of methods and terms used in surface chemical analysis (IUPAC Recommendations 2020)' on page 1809 (https://doi.org/10.1515/pac-2019-0404)