Nuclear magnetic resonance spectral regions

Figure 1.1 The electiomagnetic spectrum, showing the different microscopic excitation sources and the spectroscopies related to the different spectral regions. XRF, X-Ray Fluorescence AEFS, Absorption Edge Fine Structure EXAFS, Extended X-ray Absorption Fine Structure NMR, Nuclear Magnetic Resonance EPR, Electron Paramagnetic Resonance. The shaded region indicates the optical range.

Figure 13. Carbon 13 nuclear magnetic resonance spectra of a demulsifier blend showing the spectral regions typical of poly-oxyethylene (EO), poly-ethylene (PE), poly-propylene oxide (PO), and xylene diluents (benzene derivatives, BD). The areas under the peaks are proportional to the amount of the component in the blend.

Nuclear magnetic resonance (NMR) spectrometry is based on the net absorption of energy in the radiofrequency region of the electromagnetic spectrum by the nuclei of those elements that have spin angular momentum and a magnetic moment. For the nuclei of a particular element, characteristic absorption, or resonance frequencies, and other spectral features provide useful information on identity and molecular structure. 

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