IUPAC > Gold Book > alphabetical index > P > phonon



Elementary excitation in the quantum mechanical treatment of vibrations in a crystal lattice. An energy bundle that behaves as a particle of energy h ν, with ν the vibration frequency and h the Planck constant.
  1. A phonon can be considered as an acoustic mode of thermal vibration of a crystal lattice (or liquid helium II).
  2. Every harmonic vibration can be decomposed in phonons, which are the elementary vibrations. The total number of phonons in a system that has internal vibrations (e.g., a crystal) is related to the temperature of the system.
  3. The concept of phonons provides a simplification in the theories of thermal and electrical conduction in solids.
  4. For example, interactions between phonons and electrons are thought to be responsible for such phenomena as 'superconductivity'.
PAC, 2007, 79, 293 (Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)) on page 382
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IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997). XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8. doi:10.1351/goldbook.
Last update: 2014-02-24; version: 2.3.3.
DOI of this term: doi:10.1351/goldbook.P04547.
Original PDF version: http://www.iupac.org/goldbook/P04547.pdf. The PDF version is out of date and is provided for reference purposes only. For some entries, the PDF version may be unavailable.
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