29Si magic-angle spinning NMR study of Phillips catalysts: multi-exponential spin–lattice relaxation resulting from adsorption of paramagnetic chromium species onto a silica surface

1996 ◽  
Vol 92 (3) ◽  
pp. 453-460 ◽  
Author(s):  
John A. Chudek ◽  
Geoffrey Hunter ◽  
Glen W. McQuire ◽  
Colin H. Rochester ◽  
Terence F. S. Smith
Keyword(s):  
Silica Surface ◽  
Lattice Relaxation ◽  
Magic Angle Spinning ◽  
Spin Lattice Relaxation ◽  
Magic Angle ◽  
Chromium Species ◽  
Spin Lattice ◽  
Nmr Study ◽  
Angle Spinning

Pulse Shaped Dynamic Nuclear Polarization Under Magic Angle Spinning

2019 ◽  
Author(s):  
ASIF EQUBAL ◽  
Kan Tagami ◽  
Songi Han
Keyword(s):  
Electron Spin ◽  
Lattice Relaxation ◽  
Magic Angle Spinning ◽  
Spin Lattice Relaxation ◽  
Magic Angle ◽  
Total Electron ◽  
Spin Lattice ◽  
Maximum Benefit ◽  
Selective Saturation ◽  
Angle Spinning

In this paper, we report on an entirely novel way of improving the MAS-DNP efficiency by shaped μw pulse train irradiation for fast and broad-banded (FAB) saturation of the electron spin resonance. FAB-DNP achieved with Arbitrary Wave Generated shaped μw pulse trains facilitates effective and selective saturation of a defined fraction of the total electron spins, and provides superior control over the DNP efficiency under MAS. Experimental and quantum-mechanics based numerically simulated results together demonstrate that FAB-DNP significantly outperforms CW-DNP when the EPR-line of PAs is broadened by conformational distribution and exchange coupling. We demonstrate that the maximum benefit of FAB DNP is achieved when the electron spin-lattice relaxation is fast relative to the MAS frequency, i.e. at higher temperatures and/or when employing metals as PAs. Calculations predict that under short T<sub>1e </sub>conditions AWG-DNP can achieve as much as ~4-fold greater enhancement compared to CW-DNP.

Magic angle spinning NMR studies of silicon carbide: polytypes, impurities, and highly inefficient spin-lattice relaxation

1987 ◽  
Vol 109 (20) ◽  
pp. 6059-6067 ◽  
Author(s):  
J. Stephen Hartman ◽  
Mary F. Richardson ◽  
Barbara L. Sherriff ◽  
Beatrice G. Winsborrow
Keyword(s):  
Silicon Carbide ◽  
Lattice Relaxation ◽  
Magic Angle Spinning ◽  
Spin Lattice Relaxation ◽  
Magic Angle ◽  
Nmr Studies ◽  
Spin Lattice ◽  
Angle Spinning

An NMR thermometer for cryogenic magic-angle spinning NMR: The spin-lattice relaxation of 127I in cesium iodide

2011 ◽  
Vol 212 (2) ◽  
pp. 460-463 ◽  
Author(s):  
Riddhiman Sarkar ◽  
Maria Concistrè ◽  
Ole G. Johannessen ◽  
Peter Beckett ◽  
Mark Denning ◽  
...  
Keyword(s):  
Lattice Relaxation ◽  
Magic Angle Spinning ◽  
Cesium Iodide ◽  
Spin Lattice Relaxation ◽  
Magic Angle ◽  
Spin Lattice ◽  
Angle Spinning
Sign in / Sign up

Export Citation Format

Share Document