Spin topology

Schedletzky and Glaser, 1995, 1996). This simplified transfer function includes the special cases where = J23 = 0 (two-spin topology Hartmann and Hahn, 1962 Muller and Ernst, 1979 Braunschweiler and Ernst, 1983), (isoceles topology Listerud et al.,... 

Fast MAS. The inverse cubic dependency of the acceleration of a rotor on its diameter allows for mechanical dynamics comparable to spin dynamics in coupled spin systems. Rotor acceleration up to 300 kHz/s has been measured by Samoson and co-workers. It has been shown that this feature can be used to simplify existing experiments and explore entirely new ones in the study of spin topologies and material properties. 

The spin topology schematized in Fig. lb suggests a strategy to realize the parallel alignment of molecular spins at the scale of a lattice. 

If we have three spins, each of which is coupled to the other two, then the spectrum consists of three doublets of doublets, one centred at the shift of each of the three spins the spin topology is shown in Fig. 2.9. The appearance of these multiplets will depend on the relative sizes of the couplings. For example, if J 2 = Jn the doublet of doublets from spin 1 will collapse to a 1 2 1 triplet. On the other hand, if J 2 = 0, only doublets will be seen for spin 1 and spin 2, but spin 3 will still show a doublet of doublets. 

As stated above, genuine ferromagnetic interactions are rare however, the combination of more than two spins through the appropriate spin topology can also give rise to an unusually large spin state in the presence of antiferromagnetic interaction. A simple example is the case of... 

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