A novel approach for solid-state NMR characterization of cross-linking in polymer blends from the analysis of 1H-13C polarization transfer dynamics is introduced. It extends the model of residual dipolar couplings under permanent cross-linking, typically used to describe 1H transverse relaxation techniques, by considering a more realistic distribution of the order parameter along a polymer chain in rubbers. Based on a systematic numerical analysis,

A new heteronuclear decoupling mechanism under fast magic-angle spinning MAS is introduced. It is based on refocusing the coherences responsible for the dephase of low-γ nuclei (13C, 15N) transverse spin-polarization in the presence of strongly dipolar-coupled protons, and has the advantage that can be implemented by pulsed techniques, with all the benefits resulting from a reduced duty cycle compared with conventional decoupling by continuous rf

NMR spectroscopy is a relatively insensitive technique and many biomolecular applications operate near the limits of sensitivity and resolution. A particularly challenging example is detection of the quadrupolar nucleus 17O, due to its low natural abundance, large quadrupole couplings, and low gyromagnetic ratio. Yet the chemical shift of 17O spans almost 1000 ppm in organic molecules and it serves as a potentially unique reporter of hydrogen bonding

We describe three-dimensional magic-angle-spinning NMR experiments for the simultaneous measurement of multiple carbon-nitrogen distances in uniformly 13C,15N-labeled solids. The approaches employ transferred echo double resonance (TEDOR) for 13C-15N coherence transfer and 15N and 13C frequency labeling for site-specific resolution, and build on several previous 3D TEDOR techniques. The novel feature of the 3D TEDOR pulse sequences presented here

A new analytical method is presented for studying in a uniform way the spin dynamics in NMR experiments performed under the conditions of magic angle spinning. It was derived on the basis of formalized Floquet theory and consists of transforming the Fourier- state representation of the NMR signal into an integral one. The integral representation proves to be well suited in combination with Reyleigh-Schroedinger perturbation theory for both the fast

A general treatment of nuclear magnetic resonance (NMR) spectra under magic-angle spinning(MAS) conditions is provided that is applicable both to homogeneously and inhomogeneously broadened lines. It is based on a combination of Floquet theory and perturbation theory, and allows the factorization of the spin system response into three factors that describe different aspects of the resulting MAS spectrum. The first factor directly reflects the Floquet