The relaxation of (1)H nuclei due to their interaction with quadrupolar (14)N nuclei in gel structures is measured using fast field-cycling NMR. This phenomenon called quadrupolar dips has been reported in different (1)H-(14)N bond-rich species. In this study, we have studied quadrupolar dips in fibrin, an insoluble protein that is the core matrix of thrombi. Fibrin was formed by the addition o...

The methods of investigation of Time Reversal Invariance (TRI) violation using polarized neutron beam and polarized or aligned nuclear target are briefly considered. The new method of dynamic nuclear alignment (DNA) of quadrupolar nuclei is proposed. An implementation of this method can significantly increase the number of aligned nuclei accessible for TRI violation experiments and for the othe...

In dynamic-angle spinning (DAS), a sample spins around an axis inclined at an angle ti( t) with respect to the magnetic field such that the averages of P,(cos 6’) are zero. The simplest case is where (I(t) assumes two discrete values 8, and & (complementary DAS angles) such that the averages of PZ( cos 8) and P4( cos 0) are zero, thereby removing second-order quadrupolar (and dipolar) broadenin...

Nonsecular dipolar couplings between spin2 nuclei that are in close proximity to quadrupolar spins have been extensively documented in solid state nuclear magnetic resonance ~NMR!, particularly when involving directly bonded S5C, I5N spin pairs. These couplings arise due to the quadrupole-induced tilting of I’s nuclear spin quantization axes, and their most notable characteristic is that they c...

We demonstrate the utility of a two-pulse sequence in obtaining high-resolution solid state NMR spectra of half-integer quadrupolar nuclei with magic-angle-spinning (MAS). The experiment, which utilizes multiple/single-quantum correlation, was first described in a different form by Frydman and Harwood [J. Am. Chem. Soc. 117 (1995) 5367] and yields high-resolution isotropic NMR spectra where shi...

We show for the first time that it is possible to acquire high-resolution heteronuclear NMR correlation experiments in solid state between second-order-broadened half integer quadrupolar nuclei (i.e., 27Al and 17O) using the scalar J-coupling. The sensitivity of the experiment is dramatically improved at high fields (gain proportional to the fourth power of the principal field) with a combinati...

Semiselective heteronuclear cross-polarization for achieving coherence transfer between a spin I 5 2 scalar coupled to a spin S> 1 2 in isotropic solution is considered. The expansion of the density operator as products of irreducible tensor operators provides a compact formalism for describing cross-polarization involving scalar coupled quadrupolar nuclei. An analytical description of cross-po...

Double-rotation (DOR) is the only technique generally capable of yielding high-resolution NMR spectra of half-integer quadrupolar nuclei in one dimension for solids without the need for sophisticated coherence pathway selection. Unfortunately, due to the low outer rotor spinning frequencies currently available, the spectra often contain a large number of spinning sidebands which may overlap wit...