Thermoelectric Properties of Fe0.2Co3.8Sb12-xTex ... - Physics

Ultrafast NMR Techniques in Inhomogeneous Magnetic Fields
KowsalyaDevi Pavuluri $, # and K. V. Ramanathan #
Department of Physics $ , NMR Research Centre #
Indian Institute of Science, Bangalore
Nuclear Magnetic Resonance (NMR) enables one to probe the structure and dynamics of
matter in non-invasive manner. A major limitation of NMR for getting high resolution is the
requirement of strong and extremely homogeneous magnets. Portable NMR systems have
been built with open single sided probes for studying objects or samples whose size is limited
to fit inside the bore of the magnet. But their use remained mainly for product and quality
control since spectroscopic information cannot be recovered due to very large
inhomogeneities. Nutation echo is one of the novel techniques where RF field gradients and
static field gradients are matched to refocus static inhomogeneities but the full chemical shift
information is maintained. Multidimensional NMR experiments can be designed based on
nutation echo to get structural information in presence of inhomogeneous magnetic fields.
But multidimensional NMR experiments are inherently multi scan in nature and rely on a
series of independent acquisitions to sample the spin evolutions throughout the indirect time
domains. Spatial encoding technique enables the collection of complete multidimensional
NMR data sets in single scan. Designing experiments based on nutation echo and spatial
encoding can provide high resolution NMR spectra in inhomogeneous magnetic fields with in
fraction of a second. In this presentation, results of a 2D experiment obtained using spatial
encoding is presented. Possibilities of using this approach in the presence of inhomogeneous
magnetic fields will be discussed.
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3. Y.Shrot, Lucio Frydman J. Chem. Phys. 128, 052209 (2008)