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A phonon is a collective excitation in a periodic, elastic arrangement of atoms or molecules in condensed matter, specifically in solids and some liquids.A type of quasiparticle in physics, [1] a phonon is an excited state in the quantum mechanical quantization of the modes of vibrations for elastic structures of interacting particles.
In physics, a plasmon is a quantum of plasma oscillation.Just as light (an optical oscillation) consists of photons, the plasma oscillation consists of plasmons.The plasmon can be considered as a quasiparticle since it arises from the quantization of plasma oscillations, just like phonons are quantizations of mechanical vibrations.
If the vibration occurs lengthwise in the direction of the wave and involves contraction and relaxation of the lattice, the phonon is called a "longitudinal phonon". Alternatively, the atoms may vibrate side-to-side, perpendicular to wave propagation direction; this is known as a "transverse phonon”.
The phonon, which is either generated or annihilated, has a wavevector which is a linear combination of the incident and scattered wavevectors. This orientation will become more apparent and important when the orientation of the experimental setup is discussed. Geometric relationships between longitudinal, L, and transverse, T, acoustic waves.
A polariton is the result of the combination of a photon with a polar excitation in a material. The following are types of polaritons: Phonon polaritons result from coupling of an infrared photon with an optical phonon
These scattering mechanisms are: Umklapp phonon-phonon scattering, phonon-impurity scattering, phonon-electron scattering, and phonon-boundary scattering. Each scattering mechanism can be characterised by a relaxation rate 1/ τ {\displaystyle \tau } which is the inverse of the corresponding relaxation time.
This glossary of biology terms is a list of definitions of fundamental terms and concepts used in biology, the study of life and of living organisms.It is intended as introductory material for novices; for more specific and technical definitions from sub-disciplines and related fields, see Glossary of cell biology, Glossary of genetics, Glossary of evolutionary biology, Glossary of ecology ...
Supports national and international community of around 3000 scientists who use neutrons and muons for research in physics, chemistry, materials science, engineering, biology and more. Organisation: Owned and operated by the Science and Technology Facilities Council part of United Kingdom Research and Innovation. Website: isis.stfc.ac.uk