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Nuclear magnetic resonance
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Nuclei absorb RF in a magnetic field.
Nuclei in a magnetic field absorb radio waves at the Larmor frequency f = γB/2π (42.6 MHz/T for protons). Basis of NMR spectroscopy and MRI.
1.5 T: 63.9 MHz.
Chemical shifts give molecular structure.
In more detail
Nuclear magnetic resonance occurs when nuclear spins absorb radio waves at frequencies set by the magnetic field. The resonance frequency depends on the chemical environment of the nucleus.
Real-world uses
- NMR spectroscopy determines chemical structures in laboratories.
- MRI medical scanners use NMR principles.
- Doctors use nuclear magnetic resonance to produce MRI images that show soft tissue in detail.
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Frequently asked questions
Why does the chemical environment matter?
Electrons shield the nucleus, shifting the resonance frequency slightly.
Is NMR safe?
Yes, it uses radio frequencies and magnetic fields without ionising radiation.
What is resonance in NMR?
Nuclei absorb radio-frequency energy at a specific frequency, which depends on the magnetic field and the nucleus.
Related topics in Atomic & Nuclear Physics
Nuclear shell model · Liquid drop model · Nuclear spin and magnetic moment · Mössbauer effect · Nuclear waste · Hydrogen-like ions