Broadband excitation in magnetic resonance by self-refocusing doubly frequency-modulated pulses
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To excite and refocus single quantum coherences in a three-level system with a quadrupolar interaction, it is possible to use frequency-modulated pulses with two diverging frequency components that are swept simultaneously through the two single-quantum tr ...
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Chirp pulses were used to excite transverse magnetization over bandwidths that are .apprx.50 times wider than the amplitude of the RF field. Exptl. profiles are shown of the amplitudes and phases as a function of offset. The efficiency of refocusing by chi ...
The authors show that the accuracy of the NMR refocusing can be improved considerably by smoothing the RF amplitude and by optimizing the sweep rates. The suggested improvements are summarized graphically, and the resulting profiles are shown. Illustrative ...