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Chapter 7

Principles of Nuclear Magnetic Resonance

Kernspinresonanz (NMR): Überblick
Kernspinresonanz (NMR): Überblick
Nuclear magnetic resonance (NMR) is a phenomenon exhibited by certain nuclei that can absorb characteristic radio frequency radiation under certain ...
Atomkerne: Kernspin
Atomkerne: Kernspin
All atomic particles possess an intrinsic angular momentum, or 'spin'. Electrons, protons, and neutrons each have a spin value of ½, although ...
Atomkerne: Kernmagnetisches Moment
Atomkerne: Kernmagnetisches Moment
All atomic nuclei are positively charged. When they have a nonzero spin, they behave like rotating charges. As a consequence of their charge and spin, ...
Atomkerne: Überblick über den Kernspinzustand
Atomkerne: Überblick über den Kernspinzustand
NMR-active nuclei have energy levels called 'spin states' that are associated with the orientations of their nuclear magnetic moments. In the ...
Atomkerne: Populationsverteilung des Kernspinzustands
Atomkerne: Populationsverteilung des Kernspinzustands
Near absolute zero temperatures, in the presence of a magnetic field, the majority of nuclei prefer the lower energy spin-up state to the higher energy ...
Atomkerne: Larmor-Präzessionsfrequenz
Atomkerne: Larmor-Präzessionsfrequenz
The earth's gravitational field produces a 'twisting force' perpendicular to the angular momentum of a spinning mass (such as a spinning top) ...
Atomkerne: Magnetresonanz
Atomkerne: Magnetresonanz
The number of nuclear spins aligned in the lower energy state is slightly greater than those in the higher energy state. In the presence of an external ...
Atomkerne: Kernrelaxationsprozesse
Atomkerne: Kernrelaxationsprozesse
In the absence of an external magnetic field, nuclear spin states are degenerate and randomly oriented. When a magnetic field is applied, the spins begin ...
Atomkerne: Arten der Kernrelaxation
Atomkerne: Arten der Kernrelaxation
Relaxation in NMR systems is a first-order exponential decay and can occur by either spin–lattice or spin–spin mechanisms. Spin–lattice ...
NMR-Spektrometer: Übersicht
NMR-Spektrometer: Übersicht
NMR spectrometers consist of a strong magnet, a radiofrequency transmitter, and a detector attached to a computer console for recording spectra of samples ...
NMR-Spektrometer: Hochfrequenzpulse und Pulssequenzen
NMR-Spektrometer: Hochfrequenzpulse und Pulssequenzen
A pulse is a short burst of radio waves distributed over a range of frequencies that simultaneously excites all the nuclei in the sample. Upon passing a ...
NMR-Spektrometer: Auflösung und Fehlerkorrektur
NMR-Spektrometer: Auflösung und Fehlerkorrektur
When magnetic nuclei in a sample achieve resonance and undergo relaxation, the signal detected in NMR is an approximately exponential free induction ...
Diamagnetische Abschirmung von Kernen: lokaler diamagnetischer Strom
Diamagnetische Abschirmung von Kernen: lokaler diamagnetischer Strom
An applied magnetic field causes the electrons present in the molecule to circulate, setting up a local diamagnetic current within the molecule. The local ...
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