: In a strong external magnetic field, these nuclei align either with ( state ) or against ( state ) the field.
: Applying radiofrequency (RF) energy causes nuclei to "flip" between these states. The energy required depends on the electronic environment surrounding the nucleus, a phenomenon known as shielding .
: After excitation, nuclei return to their base state, emitting signals that are detected and processed into a spectrum. Comparison: NMR Basic 1H- and 13C-NMR Spectroscopy