3. Heterogeneous matter and nuclear magnetic resonance

Matter speciation, i.e. chemical structure and function, is crucial to physico-chemical properties. This is revealed by NMR in the form of frequency information. Every nucleus in a vacuum resonates at a characteristic frequency (the Larmor frequency). In matter, for the same nucleus, each chemical species resonates at a frequency very slightly different from the Larmor frequency. The signal is characterized by the chemical shiftδ defined below in parts per million as a relative frequency difference to be independent of the static magnetic field used ...