Nmr spectroscopy is used to study the structure of organic compounds. More nuclei are in the -spin state: differences in populations forms the basis of nmr spectroscopy. Energy difference ( e) between - and -spin states depends on strength of applied magnetic field (b0) Generates nmr spectrum: plot of signal frequency vs. Intensity: *note: right-hand side of nmr spectrum is the low-frequency side and left-hand side is the high-frequency side. Nuclei are said to be in resonance with the rf radiation. The magnetic field is proportional to the operating frequency: which is directly proportional to e. 14. 3 shielding causes different hydrogens to show signals at different. Hydrogen atoms within an organic compound do not experience the same magnetic field: nucleus is embedded within electron cloud. Effective magnetic field amount of magnetic field that the nuclei actually sense : the larger the magnetic field sensed by a proton, the higher is the frequency of the signal.