Larmor precession
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Categories: Atomic, molecular, and optical physics stubs | Precession | Electromagnetism | Atomic physics
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In physics, Larmor precession (named after Joseph Larmor) refers to the precession of the magnetic moments of electrons, atomic nuclei, and atoms about an external magnetic field. The magnetic field exerts a torque on the magnetic moment,
is the torque, Failed to parse (Missing texvc executable; please see math/README to configure.): \vec{J}
is the angular momentum vector, Failed to parse (Missing texvc executable; please see math/README to configure.): \vec{B}
is the external magnetic field, Failed to parse (Missing texvc executable; please see math/README to configure.): \times
is the cross product, and Failed to parse (Missing texvc executable; please see math/README to configure.): \ \gamma
is the gyromagnetic ratio which gives the proportionality constant between the magnetic moment and the angular momentum.
The angular momentum vector Failed to parse (Missing texvc executable; please see math/README to configure.): \vec{J} precesses about the external field axis with an angular frequency known as the Larmor frequency,
where Failed to parse (Missing texvc executable; please see math/README to configure.): \ \omega is the angular frequency and B is the magnitude of the magnetic field. A famous 1935 paper published by Lev Landau and Evgeny Lifshitz predicted the existence of ferromagnetic resonance of the Larmor precession, which was verified experimentally and independently by J. H. E. Griffiths (UK) and E. K. Zavoiskij (USSR) in 1946. Larmor precession is important in nuclear magnetic resonance. See alsobg:Прецесия и честота на Лармор de:Larmorfrequenz fa:فرکانس لارمور fr:Rayon de Larmor he:נקיפת לרמור it:Precessione di Larmor ru:Ларморовская прецессия sl:Larmorjeva frekvenca uk:Ларморівська частота |
