spin

spin

[spin]

Amount of angular momentum associated with a subatomic particle or nucleus. It is measured in multiples of planck (h-bar), equal to Planck's constant divided by 2π. Electrons, neutrons, and protons have a spin of 12, for example, while pions and helium nuclei have zero spin. The spin of a complex nucleus is the vector sum of the orbital angular momentum and intrinsic spins of the constituent nucleons. For nuclei of even mass number, the multiple is an integral; for those of odd mass number, it is a half-integer. Seealso Bose-Einstein statistics, Fermi-Dirac statistics.

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or isobaric spin or isotopic spin

Property characteristic of families of related subatomic particles differing mainly in the values of their electric charge. The families are known as isospin multiplets. The components of atomic nuclei, the neutron and the proton, form an isospin doublet since they differ only in electric charge and subsidiary properties. They are considered different versions of the same object, called a nucleon. The isospin of a nucleon has a value of 12.

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or electron paramagnetic resonance (EPR)

Technique of spectroscopic analysis (see spectroscopy) used to identify paramagnetic substances (see paramagnetism) and investigate the nature of the bonding within molecules by identifying unpaired electrons and their interaction with their immediate surroundings. Unpaired electrons, because of their spin, behave like tiny magnets and can be lined up in an applied magnetic field; energy applied by alternating microwave radiation is absorbed when its frequency coincides with that of precession of the electron magnets in the sample. The graph or spectrum of radiation absorbed as the field changes gives information valuable in chemistry, biology, and medicine.

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Spin may refer to:

In media:

In music:

In sports:

In computing:

In other uses:

  • Spin group, a particular double cover of the special orthogonal group SO(n)
  • Metal spinning, the process of forming metal over a mandrel while spinning around a lathe
  • Sufi spinning, a twirling meditation
  • Fokker Spin, an airplane built by Anthony Fokker

See also

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