Hadamard spectroscopy

Polarization can be transferred simultaneously within several spin pairs without cross-talk if different rf amplitudes are used for each pair of spins in the multiply selective irradiation scheme. This principle has been used in Hartmann-Hahn Hadamard spectroscopy (HAHAHA), where a phaseencoding scheme is used to separate simultaneously acquired spectra that represent individual doubly selective Hartmann-Hahn transfer experiments (Kupce and Freeman, 1993e). 

Hartmann-Hahn-Hadamard spectroscopy Heteronuclear Hartmann-Hahn spectroscopy Heteronuclear-homonuclear Hartmann-Hahn spectroscopy... 

Kupce E, Freeman R (2003) Fast multi-dimensional Hadamard spectroscopy. J Magn Reson 163 56-63... 

Time reduction in homonuclear spectra using Hadamard spectroscopy Time reduction in heteronuclear spectra using Hadamard spectroscopy GFT NMR experiments for resonance assignments... 

Hadamard Spectroscopy. If. instead of the exit slit, an irregular arrangement of slits of various widths is used, and an arrangement in the form of a comb-like second slit is moved in front of this, for each relative position a different summation of intensities at various wavelengths is obtained on a nonmultiplex detector. By using convolution functions. spectra can be computed rapidly for a cycle of different slit positions. Since for mathematical deconvolution so-called Hadamard matrices are used, the principle is known as Hadamard spectroscopy. It has gained some importance in waste gas analysis [50]. 

Keywords Hadamard spectroscopy Multidimensional NMR Multiple Parallel acquisition NMR Projection reconstruction... 

Structure determination of soluble proteins of moderate size (up to 30 kDa) by multinuclear multidimensional NMR spectroscopy is now fairly standard with well-established protocols. In the chapter NMR with Multiple Receivers, an acquisition scheme employing multiple receivers is described which allows for faster structure determination in small molecules. Further, recently employed fast acquisition schemes such as Hadamard spectroscopy, projection-reconstruction techniques, and reduced dimensionality experiments are explained. 

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