Term: photon
https://doi.org/10.1351/goldbook.P04627

Definition:
Particle of zero charge, zero rest mass, spin quantum number 1, energy hν and momentum hν/c(h is the Planck constant, ν the frequency of radiation and c the speed of light), carrier of electromagnetic force.

Related Terms:
1) momentum (http://doi.org/10.1351/goldbook.M04007).
2) planck constant (http://doi.org/10.1351/goldbook.P04685).
3) carrier (http://doi.org/10.1351/goldbook.C00859).

Source: Green Book, 2nd ed., p. 93 (https://goldbook.iupac.org/files/pdf/green_book_2ed.pdf)

Citation: 'photon' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.P04627

License: The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) for individual terms.

Disclaimer: The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using.