Double-Quantum Filtration under Rotational-Resonance Conditions: Numerical Simulations and Experimental Results

Double-Quantum Excitation in the NMR of Spinning Solids by Pulse-Assisted Rotational Resonance

“…Again, there is good agreement with the simulated curves, with the remaining differences being attributable to relaxation. The rapid oscillations in the excitation profile have been observed before (29). Figure 7b shows the corresponding results for the sequence in Fig.…”

“…The method has been shown to be very effective, even in molecular systems with a fairly large internuclear distance (19). The technique has also been applied to systems of more than two spins (29). However, the overall signal amplitude in this experiment is degraded by the necessity of acquiring the NMR signals under rotational resonance conditions.…”

Double-Quantum Filtered MAS NMR in the Presence of Chemical Shielding Anisotropies and Direct Dipolar and JCouplings

“…With one of the two 119 Sn chemical shielding tensors in 1 being axially symmetric, η CS 2 = 0 (see Table 1 (12,13). Some additional numerical investigations employed iterative lineshape fitting methods.…”

Dipolar and J Encoded DQ MAS Spectra under Rotational Resonance

“…In addition to radiofrequency techniques (4)(5)(6)(7)(8)(9)(10)(11)(12), in homonuclear systems recoupling methods also have been developed (13)(14)(15)(16)(17) that exploit the socalled rotational resonance (R 2 ) phenomenon (19). By this, one can selectively reintroduce part of the dipolar interaction between two chemically distinct nuclear sites, j and k, provided that their isotropic chemical shift difference matches a small integer multiple of the rotor frequency, i.e., δ jk = ω j −ω k = nω R .…”

“…Unlike the case presented in Refs. (16,17), the transverse magnetization is employed here as an initial state, which is then converted into DQ coherences using an excitation scheme similar to that reported in Ref. (13).…”