Carbon-13 NMR Spectroscopy
Carbon-13 NMR spectroscopy is the application of nuclear magnetic resonance to the isotope of carbon-12.
The isotope is used because the Carbon-13 nucleus behaves like a little magnet, which means that it can either be aligned with an external magnetic field or opposed to it.
After the alignment of the nuclear spins by a constant magnetic field, a radiofrequency pulse is used to perturb it. The pulse is applied perpendicular to the constant field, and its frequency is adjusted in order to generate the desired NMR signal.
Only isotopes that have an odd number of protons/neutrons have nonzero spins and are active in NMR experiments such as 13C, 1H, and 15N.