Improving the sensitivity of J coupling measurements in solids with application to disordered materials

Guerry, Paul and Brown, Steven P. and Smith, Mark Edmund (2016) Improving the sensitivity of J coupling measurements in solids with application to disordered materials. AIP Advances, 6 (5). ISSN 2158-3226

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Abstract

It has been shown previously that for magic angle spinning (MAS) solid state NMR the refocused INADEQUATE spin-echo (REINE) experiment can usefully quantify scalar (J) couplings in disordered solids. This paper focuses on the two z filter components in the original REINE pulse sequence, and investigates by means of a product operator analysis and fits to density matrix simulations the effects that their removal has on the sensitivity of the experiment and on the accuracy of the extracted J couplings. The first z filter proves unnecessary in all the cases investigated here and removing it increases the sensitivity of the experiment by a factor ∼1.1–2.0. Furthermore, for systems with broad isotropic chemical shift distributions (namely whose full widths at half maximum are greater than 30 times the mean J coupling strength), the second z filter can also be removed, thus allowing whole-echo acquisition and providing an additional √2 gain in sensitivity. Considering both random and systematic errors in the values obtained, J couplings determined by fitting the intensity modulations of REINE experiments carry an uncertainty of 0.2–1.0 Hz (∼1−10 %).

Item Type:
Journal Article
Journal or Publication Title:
AIP Advances
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/3100
Subjects:
Departments:
ID Code:
80978
Deposited By:
Deposited On:
17 Aug 2016 08:40
Refereed?:
Yes
Published?:
Published
Last Modified:
26 May 2020 05:08