Higher order coherences

In the case of spins-1 to the number of pairs of satellite transitions increases and is given by / —. Adiabaticity arguments show that interconversion, during sample spinning, of higher-order coherences with SQC may be achieved with a single FAM pulse... 

When excitation of higher-order coherences are sought, P (t) blocks may be added right after a 3Q excitation Ph pulse and optimized in the same manner as above with the sole difference that blocks are inserted in increasing order of their modulation frequencies. Here, we should point out the it may be beneficial to insert FAM-II blocks rather than FAM-I blocks to provide better transfer of 3Q MQ. Sometimes, the composite pulse applied cannot be really classified as FAM-I or FAM-II and a good example is the single x — x scheme used in Refs. 78 and 97. 

Figure 7.11 NMR on a chip the scheme shows the architecture of the heterojunction built by Yusa and co-workers in 2005, containing part of a NMR hardware integrated to it. In a conventional NMR expmment only first- der coherences are observed. In Yiisa et al. expa-iment, higher order coherences are directly measured through the resistance variation measured across the split gate. The resistance depends on the nuclear magnetic state. Adapted with permission from [20].

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