ID NMR Separation of overlapping powder patterns by selective fr irradiation and switching-angle spinning

Hadamard NMR spectroscopy in solids

The duration of 2D and 3D NMR experiments in solids can be reduced by several orders of magnitude by using frequency domain Hadamard encoding with long selective pulses. We demonstrate Hadamard encoded experiments in (13)C enriched solids samples. To avoid multiple quantum interferences, the Hadamard encoding pulses are applied sequentially rather than simultaneously in this study. Among other possible applications, dipolar assisted rotational resonance experiments and measurement of NOESY type build-up rates in proton driven spin diffusion are demonstrated.

Switching-angle sample spinning NMR probe with a commercially available 20 kHz spinning system

A switching-angle sample spinning (SASS) probe workable at high spinning speeds was developed using a commercially available rotor/housing system. Details of the construction are described. As application examples of the SASS probe, we report experiments of powder pattern separation at the spinning speed of 20 kHz and broadband 13C-13C polarization transfer at 16 kHz.

Off-angle correlation spectroscopy applied to spin-1/2 and quadrupolar nuclei

A two-dimensional correlation experiment is described, in which homonuclear dipolar couplings are used to realize through-space magnetization exchange on spin-1/2 (31P) and on quadrupolar nuclei (23Na and 11B). In the detection period, Magic Angle Spinning is applied to enhance resolution, and the dipole couplings are re-introduced in the mixing period by spinning off the Magic Angle. The dependency of the exchange rates on the mixing time and the spinning angle is investigated. The influence of strong spin-locking during mixing is discussed, and shown in the spin-1/2 case to remove the dependence on chemical shift offset effects. For quadrupolar spins, the experiment yields information on the relative tensor orientations of the coupled quadrupoles. Applications to crystalline sodium aluminum diphosphate, sodium sulphite, and potassium borate glasses are shown.