Nuclear magnetic resonance (NMR) is a quantum-mechanical phenomenon in which atomic nuclei possessing a non-zero magnetic moment absorb and re-emit electromagnetic energy when placed in a static magnetic field and irradiated by resonant radiofrequency radiation [1]. In a static field B0, spin-active nuclei precess at the Larmor frequency, which is proportional to B0 and the magnetogyric ratio; the ensemble magnetization then relaxes back toward equilibrium through longitudinal (T1) and transverse (T2) processes described by the Bloch equations [2]. Because the resonant frequency depends on the local electronic environment, the resonance position of a nucleus carries information about its chemical bonding and neighborhood, forming the basis of NMR spectroscopy [3]. The term also covers magnetic resonance imaging, in which spatial gradients encode the resonant signal to produce tomographic images of internal structures [4]. NMR is distinguished from other magnetic resonances by the involvement of nuclear spin rather than electron spin, and from absorption spectroscopy by the use of radiofrequency excitation and phase-sensitive detection [5].
- nuclear magnetic resonance
- NMR
- nuclear spin
- Larmor precession
Advanced MRI Techniques and Applications • Radiology, Nuclear Medicine and Imaging • Medicine • Health Sciences
References
- F. Bloch; Nuclear Induction. Phys. Rev. B 1946, 70, 460-474, 10.1103/physrev.70.460.
- Abragam, A. The Principles of Nuclear Magnetism; Oxford University Press: Oxford, 1961. https://global.oup.com/academic/product/the-principles-of-nuclear-magnetism-9780198520146?cc=cn&lang=en&
- Ernst, R.R.; Bodenhausen, G.; Wukaun, A. Principles of Nuclear Magnetic Resonance in One and Two Dimensions; Oxford University Press: Oxford, 1987. https://global.oup.com/academic/product/principles-of-nuclear-magnetic-resonance-in-one-and-two-dimensions-9780198556473?cc=cn&lang=en&
- Robert W. Brown; Yu‐Chung N. Cheng; E. Mark Haacke; Michael R. Thompson; Ramesh Venkatesan. Magnetic Resonance Imaging; Wiley: Hoboken, NJ, United States, 2014. [CrossRef]
- Levitt, M.H. Spin Dynamics: Basics of Nuclear Magnetic Resonance, 2nd ed.; Wiley: Chichester, UK, 2008. https://www.wiley.com/en-us/shop/general-chemistry/spin-dynamics-basics-of-nuclear-magnetic-resonance-2nd-edition-p-9781118681848