Selection of intra- or inter-molecular multiple-quantum coherences in NMR of highly polarized solution

Localized intermolecular zero‐quantum coherence spectroscopy in vivo

“…2(a) already illustrates that refocusing under the DDF is a local process and will not be disturbed by field variations on a scale large compared to (gGT) 21 . A more detailed analysis shows, that signal formed at the centre of a spherical sample with volume V depends on the integral (13):…”

“…For multi-component systems, theoretical analysis is performed either by density matrix or classical calculations (11, 15, 18, 21, 27-31, 37, 45, 54-68). Analytical description of spectral patterns created by the joint effect of intermolecular dipolar couplings, and intramolecular J-couplings has been provided in a quantum treatment (21,66,69). However, a general analytical solution for iMQC signal evolution including the effects of diffusion and relaxation is still not available.…”

“…2(b), bottom]. The time scale of this process depends on the maximum frequency of the DDF (x d ), which is the reciprocal of the dipolar time constant s d 5 (gl 0 M 0 ) 21 , also called demagnetizing time. If the second pulse is applied with 908 instead of 458, the local intensity of the DDF and also x d will be maximal.…”

“…Figure 3 depicts the signal contribution from spherical shells as function of r by showing the solution of Eq. [3] for k m 5 100 mm 21 . Largest contribution is obtained from nearby spins, roughly between r cutoff and 5/k m .…”

“…Now, we approximate the DDF peak line shape. For a gradient modulation of k m 5 100 mm 21 , major contribution to the DDF signal comes from interactions within a sphere with roughly 50 lm radius for each individual spin. Therefore, only a 100 lm section of the frequency distribution function around the actual position r n is considered (dx n ).…”