화학공학소재연구정보센터
Chemical Physics Letters, Vol.470, No.4-6, 318-324, 2009
Determination of absolute quadrupolar tensor orientations by double-quantum NMR on powders
We introduce a new nuclear magnetic resonance (NMR) approach for determining electric field gradient ('quadrupolar') tensor orientations directly from polycrystalline powders. It involves a homonuclear 2D experiment that correlates (two-spin) double-quantum and single-quantum coherences of half-integer quadrupolar spin nuclei undergoing magic-angle-spinning. The 2D NMR spectrum is sensitive both to the relative orientations between the correlated quadrupolar tensors and to their orientations relative to the dipolar vector of the spin-pair. A novel strategy to calculate 2D spectra from multi-spin systems is used to extract the tensor orientations. We demonstrate the method by estimating the three Na-23 quadrupolar tensor orientations in Na2SO3. (C) 2009 Elsevier B. V. All rights reserved.