P1253553538KcCWb

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Unexpected Resolution and Sensitivity Enhancement
at High Field (900 MHz) Solid State NMRPI
Riqiang Fu and Naresh S. Dalal, National High
Magnetic Field Laboratory and Florida State
University
In nuclear magnetic resonance (NMR) of spin-1/2
nuclei, the spectral resolution is known to
improve linearly with an increase of static
magnetic field B0, while the sensitivity is
expected to be proportional to (B0)3/2.
Our recent 15N NMR measurements on ammonium
dihydrogen arsenate (ADA) indicated that there
exists a line-narrowing effect in spin-1/2 nuclei
in solids that was not demonstrated before. Such
a line-narrowing effect results in simultaneous
resolution and sensitivity enhancement at high
fields beyond what are expected from the theory
(see figures left). The improved resolution and
sensitivity at the ultra-wide bore 900 MHz
(right) at the National High Magnetic Field
Laboratory enable us to probe the nature of the
antiferroelectric phase transition in ADA to a
depth not possible at lower fields and indicate
potential for new applications in materials
science. This research shows for the first time
that it is highly desirable to develop NMR at
still higher fields, because the expected
benefits to the power of the technique could well
outweigh  the added costs.
High-resolution 15N NMR spectra of NH4H2AsO4
(ADA) showing improved resolution and sensitivity
at high fields
Resolution and sensitivity enhancement factors
at high fields
Fu, R. Sen, O.G. and Dalal, N.S., Simultaneous
Supralinear Line-Narrowing and Sensitivity
Enhancement at High Fields in Magic Angle
Spinning NMR of Spin-1/2 Nuclei in Solids,
Journal of the American Chemical Society 129,
470-471 (2007)