Nuclear Overhauser effect spectroscopy Fourier transform

We have seen that the nuclear Overhauser effect can provide information about internuclear distances through analysis of enhancement patterns in the NMR spectrum before and after saturation of selected resonances. In nuclear Overhauser effect spectroscopy (NOESY) a map of all possible NOE interactions is obtained by again using a proper choice of radiofrequency pulses and Fourier transformation techniques. Like a COSY spectrum, a NOESY spectrum consists of a series of diagonal peaks that correspond to the onedimensional NMR spectrum of the sample. The off-diagonal peaks indicate which nuclei are close enough to each other to give rise to a nuclear Overhauser effect. NOESY data reveal internuclear distances up to about 0.5 nm. 

Figure 3.24 The pulse sequence for two-dimensional nuclear Overhauser effect spectroscopy (NOESY), The pulse sequence is divided into the preparation (P), evolution or tx (E), mixing (M), and detection or t2 (D) periods. The data are recorded in the detection period for many equally spaced values of tx and double Fourier-transformed to give the two-dimensional frequency spectrum.

In addition to the specific references given in the chapter, much of the classic treatment of relaxation comes from the book by Abragam,33 but there are many other discussions of this subject in almost every book on NMR. Additional details along the lines presented here are given in Pulse and Fourier Transform NMR by Thomas C. Farrar and Edwin D. Becker,97 Nuclear Magnetic Resonance Spectroscopy by Robin K. Harris,32 and The Nuclear Overhauser Effect in Structural and Conformational Analysis by D. Neuhaus and M. P. Williamson.98... 

See also Chemical Exchange Effects in NMR Fourier Transformation and Sampling Theory NMR Relaxation Rates NMR Spectrometers Nuclear Overhauser Effect Parameters in NMR Spectroscopy, Theory of. 

Systems EPR Imaging EPR Spectroscopy, Theory Fluorescence Polarization and Anisotropy Fourier Transformation and Sampling Theory Laboratory Information Management Systems (LIMS) NMR in Anisotropic Systems, Theory NMR Pulse Sequences NMR Relaxation Rates Nuclear Overhauser Effect Spin Trapping and Spin Labelling Studied Using EPR Spectroscopy. 

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