Anisotropy pattern

Fig. 2 Schematic representation of the 13C NMR signal of a single crystal containing the functional group AB, oriented (A) perpendicular to the applied field, and (B) parallel to the applied field. The lineshape in (C) represents the NMR signal of a polycrystalline sample with a random distribution of orientations yielding the chemical shift anisotropy pattern displayed. (From Ref. 15.)...

NMA. This was attributed to the motion in the backbone which reduces the anisotropy pattern. This should signify that the rigidities are in the order of piperidine... 

Finally H NMR 77h in (mni -NT-PA is mentioned briefly. The anisotropy pattern of H NMR T h in (roti.s-S-PA has been reported to be basically understandable with neutral soliton diffusion [62]. Does it hold even for (ro .f-NT-PA The angular dependence of 7]]j is shown in Figure 6.14 [24]. It is noteworthy that the depression around > = 90° is deeper than that in b-atu-S-PA and the origin of such a depression cannot be expected firom the diffusion mechanism of the neutral solitons as depicted by the solid curve B in Figure 6.14. To account for such a depression by another mechanism, spectral diffusion and localized. spins as described in (6.18) (see, [8] p. 379) [8,83] it is... 

As shown in Figures 14.5 and 14.6, the axial extensional stiffness C33 and axial Young s modulus 3 rise sharply with increasing k but become saturated above k — A, closely following the behavior of P and P. The transverse extensional stiffness transverse Young s modulus and the axial (C ) and transverse (C ) shear moduli show moderate decreases while the cross-plane stiffness C 3 exhibits a slight increase. The anisotropy patterns of C33 3 and... 

The shear moduli also exhibit strong anisotropy in the top or bottom layers (Figure 14.12a). The anisotropy pattern of reflects the preferential chain orientation parallel to the 1-3 plane. Figure 14.12b shows that the shear moduli differ by less than 20% in the core, in agreement with the above results on the extensional stiffnesses. The fact that on the edges of the middle layer... 

Figure 16 Spectral lineshapes for powdered solids. (A) Peak doublet produced by dipole coupling between two spin 1/2 nuclei. The doublet is composed of two parts (shown dotted). They correspond to the observed proton flip occurring when its neighbor is spin up (left) or spin down (right). The indicated turning points correspond to the angle between the internuclear vector and 5b. (B) Chemical shift anisotropy pattern with shielding tensor components (Til, < 22. and (T33. (C) Combined DD and CSA spectrum. Note that this is not simply (A) -1- (B). (Reproduced with permission from Power WP and Wasylishen RE (1991) In Webb GA (ed.) Annual Reports in NMR Spectroscopy, vol. 23, p. 17. London Academic Press.)...

To overcome this problem, Kervem et al. explored the potential for structural investigation contained in the anisotropies of nuclei, for which CSA is negligible. shift anisotropy patterns in a class of lanthanide compounds were recorded at high-resolution in an adiabatic TEDOR experiment [45], and were shown to... 

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