Two-dimensional nuclear magnetic resonance with sample flip for characterizing orientation distributions, and its analogy to x-ray scattering

Abstract

Twodimensional exchange nuclear magnetic resonance of powder samples. IV. Distribution of correlation times and line shapes in the intermediate dynamic range J. Chem. Phys. 97, 7944 (1992); 10.1063/1.463469The determination of the reorientational angle distribution in twodimensional exchange nuclear magnetic resonance spectroscopy on powder samples Twodimensional exchange nuclear magnetic resonance of powder samples. III. Transition to motional averaging and application to the glass transition

Determination of Molecular Orientational Order in Cold-Stretched Poly(p-phenylene vinylene) Thin Films by DECODER 13C NMR

“…6b and 6d) reflect the characteristic elliptical features for reorientation by a discrete flip angle [25,26,28]. In DECODER NMR, even for Za0; elliptical patterns (which are also characteristic for Z ¼ 0) are observed, though they appear as threefold overlapping features in powder spectra.…”

“…The DECODER method is an extension of an earlier experiment first introduced by Henrichs [27], which applied a discrete macroscopic reorientation of a sample to determine orientation distribution moments for films of poly(ethylene terephthalate) (PET) [27]. DECODER NMR extends Henrichs's approach to include reconstruction of the orientation distribution and has been implemented to study orientational order in deuterated polyethylene films [25], PET films and fibers [28], and high tensile strength fibers of poly(p-phenyleneterephthalamide) [29].…”

“…The purpose of this study is to quantify molecular orientation distributions in cold-stretched PPV films, by applying the solid-state direction exchange with correlation for orientation-distribution evaluation and reconstruction (DECODER) NMR technique [25,26]. This method can access both crystalline and amorphous regions of polymer films (like IR dichroism, though unlike X-ray scattering).…”

The molecular structure of spider dragline silk: Folding and orientation of the protein backbone

“…2, we tried to extract the orientational distribution function P(␣ F , ␤ F ) by using a regulatory approach equivalent to that used for the DOQSY spectra. The regulatory analysis did not yield a stable result, though, and we resorted to measuring 2D spectra, which correlate the 1D spectra at two different sample orientations [DECODER spectroscopy (42,43)]. Experimental DECODER spectra, fits, and PDFs for an experiment 60°3 30°are shown in Fig.…”

Determination of Orientational Anisotropy in Glassy Solids by 2D Dipolar Spectra With Sample Flipping

“…Later, Schmidt-Rohr et al X-ray and neutron scattering have been used extensively coined the acronym DECODER for this experiment (8,9). It to measure the preferential orientation of crystallites in has so far been applied to CSA tensor (8,9) and quadrupolar semicrystalline polymers ( 3,4 ) . However, in amorphous tensor (8) measurements.…”