Hahn’s echo

The so-called SEDOR technique (spin-echo double resonance [9, 47, 48], see Fig. 5) allows the determination of internuclear distances, rjs, for isolated spin pairs consisting of a resonating J-spin and a non-resonating S-spin. Hahn s echo [49] of the resonating J-spins is observed with a time between the 7i/2-pulse and the 7T-pulse. A rr-pulse applied to the S-spins after a variable time ti (0characteristic damping of Hahn s echo of the resonating /-spins. The damped amplitude, of Hahn s echo under SEDOR conditions is determined by ... 

Fig. 5. Schematic representation of a SEDOR experiment. The pulse sequence applied to the resonating S-spins corresponds to the weU-known Hahn s echo experiment...

Fig.l Structure of a free bridging hydroxyl group in the framework of zeolites, according to a quantum chemical calculation [18] and NMR spectrum of an activated 0.3 HNa - Y zeolite (Si/Al = 2.5) measured at 500 MHz. The spectra were recorded by the use of Hahn s echo in order to avoid problems with the dead time of the receiver [19]. This sample almost exclusively contains free bridging hydroxyl groups... 

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See also in sourсe #XX -- [ ]

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